Search Results: "ed"

10 May 2022

Russell Coker: Elon and Free Speech

Elon Musk has made the news for spending billions to buy a share of Twitter for the alleged purpose of providing free speech. The problem with this claim is that having any company controlling a large portion of the world s communication is inherently bad for free speech. The same applies for Facebook, but that s not a hot news item at the moment. If Elon wanted to provide free speech he would want to have decentralised messaging systems so that someone who breaks rules on one platform could find another with different rules. Among other things free speech ideally permits people to debate issues with residents of another country on issues related to different laws. If advocates for the Russian government get kicked off Twitter as part of the American sanctions against Russia then American citizens can t debate the issue with Russian citizens via Twitter. Mastodon is one example of a federated competitor to Twitter [1]. With a federated messaging system each host could make independent decisions about interpretation of sanctions. Someone who used a Mastodon instance based in the US could get a second account in another country if they wanted to communicate with people in countries that are sanctioned by the US. The problem with Mastodon at the moment is lack of use. It s got a good set of features and support for different platforms, there are apps for Android and iPhone as well as lots of other software using the API. But if the people you want to communicate with aren t on it then it s less useful. Elon could solve that problem by creating a Tesla Mastodon server and give a free account to everyone who buys a new Tesla, which is the sort of thing that a lot of Tesla buyers would like. It s quite likely that other companies selling prestige products would follow that example. Everyone has seen evidence of people sharing photos on social media with someone else s expensive car, a Mastodon account on ferrari.com or mercedes.com would be proof of buying the cars in question. The number of people who buy expensive cars new is a very small portion of the world population, but it s a group of people who are more influential than average and others would join Mastodon servers to follow them. The next thing that Elon could do to kill Twitter would be to have all his companies (which have something more than a dozen verified Twitter accounts) use Mastodon accounts for their primary PR releases and then send the same content to Twitter with a 48 hour delay. That would force journalists and people who want to discuss those companies on social media to follow the Mastodon accounts. Again this wouldn t be a significant number of people, but they would be influential people. Getting journalists to use a communications system increases it s importance. The question is whether Elon is lacking the vision necessary to plan a Mastodon deployment or whether he just wants to allow horrible people to run wild on Twitter. The Verge has an interesting article from 2019 about Gab using Mastodon [2]. The fact that over the last 2.5 years I didn t even hear of Gab using Mastodon suggests that the fears of some people significantly exceeded the problem. I m sure that some Gab users managed to harass some Mastodon users, but generally they were apparently banned quickly. As an aside the Mastodon server I use doesn t appear to ban Gab, a search for Gab on it gave me a user posting about being pureblood at the top of the list. Gab claims to have 4 million accounts and has an estimated 100,000 active users. If 5.5% of Tesla owners became active users on a hypothetical Tesla server that would be the largest Mastodon server. Elon could demonstrate his commitment to free speech by refusing to ban Gab in any way. The Wikipedia page about Gab [3] has a long list of horrible people and activities associated with it. Is that the free speech to associate with Tesla? Polestar makes some nice electric cars that appear quite luxurious [4] and doesn t get negative PR from the behaviour of it s owner, that s something Elon might want to consider. Is this really about bragging rights? Buying a controlling interest in a company that has a partial monopoly on Internet communication is something to boast about. Could users of commercial social media be considered serfs who serve their billionaire overlord?
Related posts:
  1. Car Drivers vs Mechanics and Free Software In a comment on my post about Designing Unsafe Cars...
  2. Healthcare and Free Software The Washington Monthly has an interesting article about healthcare and...
  3. free software liason? In my previous work as a sys-admin I have worked...

Melissa Wen: Multiple syncobjs support for V3D(V) (Part 2)

In the previous post, I described how we enable multiple syncobjs capabilities in the V3D kernel driver. Now I will tell you what was changed on the userspace side, where we reworked the V3DV sync mechanisms to use Vulkan multiple wait and signal semaphores directly. This change represents greater adherence to the Vulkan submission framework. I was not used to Vulkan concepts and the V3DV driver. Fortunately, I counted on the guidance of the Igalia s Graphics team, mainly Iago Toral (thanks!), to understand the Vulkan Graphics Pipeline, sync scopes, and submission order. Therefore, we changed the original V3DV implementation for vkQueueSubmit and all related functions to allow direct mapping of multiple semaphores from V3DV to the V3D-kernel interface. Disclaimer: Here s a brief and probably inaccurate background, which we ll go into more detail later on. In Vulkan, GPU work submissions are described as command buffers. These command buffers, with GPU jobs, are grouped in a command buffer submission batch, specified by vkSubmitInfo, and submitted to a queue for execution. vkQueueSubmit is the command called to submit command buffers to a queue. Besides command buffers, vkSubmitInfo also specifies semaphores to wait before starting the batch execution and semaphores to signal when all command buffers in the batch are complete. Moreover, a fence in vkQueueSubmit can be signaled when all command buffer batches have completed execution. From this sequence, we can see some implicit ordering guarantees. Submission order defines the start order of execution between command buffers, in other words, it is determined by the order in which pSubmits appear in VkQueueSubmit and pCommandBuffers appear in VkSubmitInfo. However, we don t have any completion guarantees for jobs submitted to different GPU queue, which means they may overlap and complete out of order. Of course, jobs submitted to the same GPU engine follow start and finish order. A fence is ordered after all semaphores signal operations for signal operation order. In addition to implicit sync, we also have some explicit sync resources, such as semaphores, fences, and events. Considering these implicit and explicit sync mechanisms, we rework the V3DV implementation of queue submissions to better use multiple syncobjs capabilities from the kernel. In this merge request, you can find this work: v3dv: add support to multiple wait and signal semaphores. In this blog post, we run through each scope of change of this merge request for a V3D driver-guided description of the multisync support implementation.

Groundwork and basic code clean-up: As the original V3D-kernel interface allowed only one semaphore, V3DV resorted to booleans to translate multiple semaphores into one. Consequently, if a command buffer batch had at least one semaphore, it needed to wait on all jobs submitted complete before starting its execution. So, instead of just boolean, we created and changed structs that store semaphores information to accept the actual list of wait semaphores.

Expose multisync kernel interface to the driver: In the two commits below, we basically updated the DRM V3D interface from that one defined in the kernel and verified if the multisync capability is available for use.

Handle multiple semaphores for all GPU job types: At this point, we were only changing the submission design to consider multiple wait semaphores. Before supporting multisync, V3DV was waiting for the last job submitted to be signaled when at least one wait semaphore was defined, even when serialization wasn t required. V3DV handle GPU jobs according to the GPU queue in which they are submitted:
  • Control List (CL) for binning and rendering
  • Texture Formatting Unit (TFU)
  • Compute Shader Dispatch (CSD)
Therefore, we changed their submission setup to do jobs submitted to any GPU queues able to handle more than one wait semaphores. These commits created all mechanisms to set arrays of wait and signal semaphores for GPU job submissions:
  • Checking the conditions to define the wait_stage.
  • Wrapping them in a multisync extension.
  • According to the kernel interface (described in the previous blog post), configure the generic extension as a multisync extension.
Finally, we extended the ability of GPU jobs to handle multiple signal semaphores, but at this point, no GPU job is actually in charge of signaling them. With this in place, we could rework part of the code that tracks CPU and GPU job completions by verifying the GPU status and threads spawned by Event jobs.

Rework the QueueWaitIdle mechanism to track the syncobj of the last job submitted in each queue: As we had only single in/out syncobj interfaces for semaphores, we used a single last_job_sync to synchronize job dependencies of the previous submission. Although the DRM scheduler guarantees the order of starting to execute a job in the same queue in the kernel space, the order of completion isn t predictable. On the other hand, we still needed to use syncobjs to follow job completion since we have event threads on the CPU side. Therefore, a more accurate implementation requires last_job syncobjs to track when each engine (CL, TFU, and CSD) is idle. We also needed to keep the driver working on previous versions of v3d kernel-driver with single semaphores, then we kept tracking ANY last_job_sync to preserve the previous implementation.

Rework synchronization and submission design to let the jobs handle wait and signal semaphores: With multiple semaphores support, the conditions for waiting and signaling semaphores changed accordingly to the particularities of each GPU job (CL, CSD, TFU) and CPU job restrictions (Events, CSD indirect, etc.). In this sense, we redesigned V3DV semaphores handling and job submissions for command buffer batches in vkQueueSubmit. We scrutinized possible scenarios for submitting command buffer batches to change the original implementation carefully. It resulted in three commits more: We keep track of whether we have submitted a job to each GPU queue (CSD, TFU, CL) and a CPU job for each command buffer. We use syncobjs to track the last job submitted to each GPU queue and a flag that indicates if this represents the beginning of a command buffer. The first GPU job submitted to a GPU queue in a command buffer should wait on wait semaphores. The first CPU job submitted in a command buffer should call v3dv_QueueWaitIdle() to do the waiting and ignore semaphores (because it is waiting for everything). If the job is not the first but has the serialize flag set, it should wait on the completion of all last job submitted to any GPU queue before running. In practice, it means using syncobjs to track the last job submitted by queue and add these syncobjs as job dependencies of this serialized job. If this job is the last job of a command buffer batch, it may be used to signal semaphores if this command buffer batch has only one type of GPU job (because we have guarantees of execution ordering). Otherwise, we emit a no-op job just to signal semaphores. It waits on the completion of all last jobs submitted to any GPU queue and then signal semaphores. Note: We changed this approach to correctly deal with ordering changes caused by event threads at some point. Whenever we have an event job in the command buffer, we cannot use the last job in the last command buffer assumption. We have to wait all event threads complete to signal After submitting all command buffers, we emit a no-op job to wait on all last jobs by queue completion and signal fence. Note: at some point, we changed this approach to correct deal with ordering changes caused by event threads, as mentioned before.

Final considerations With many changes and many rounds of reviews, the patchset was merged. After more validations and code review, we polished and fixed the implementation together with external contributions: Also, multisync capabilities enabled us to add new features to V3DV and switch the driver to the common synchronization and submission framework:
  • v3dv: expose support for semaphore imports
    This was waiting for multisync support in the v3d kernel, which is already available. Exposing this feature however enabled a few more CTS tests that exposed pre-existing bugs in the user-space driver so we fix those here before exposing the feature.
  • v3dv: Switch to the common submit framework
    This should give you emulated timeline semaphores for free and kernel-assisted sharable timeline semaphores for cheap once you have the kernel interface wired in.
We used a set of games to ensure no performance regression in the new implementation. For this, we used GFXReconstruct to capture Vulkan API calls when playing those games. Then, we compared results with and without multisync caps in the kernelspace and also enabling multisync on v3dv. We didn t observe any compromise in performance, but improvements when replaying scenes of vkQuake game.

Melissa Wen: Multiple syncobjs support for V3D(V) (Part 1)

As you may already know, we at Igalia have been working on several improvements to the 3D rendering drivers of Broadcom Videocore GPU, found in Raspberry Pi 4 devices. One of our recent works focused on improving V3D(V) drivers adherence to Vulkan submission and synchronization framework. We had to cross various layers from the Linux Graphics stack to add support for multiple syncobjs to V3D(V), from the Linux/DRM kernel to the Vulkan driver. We have delivered bug fixes, a generic gate to extend job submission interfaces, and a more direct sync mapping of the Vulkan framework. These changes did not impact the performance of the tested games and brought greater precision to the synchronization mechanisms. Ultimately, support for multiple syncobjs opened the door to new features and other improvements to the V3DV submission framework.

DRM Syncobjs But, first, what are DRM sync objs? 
* DRM synchronization objects (syncobj, see struct &drm_syncobj) provide a
* container for a synchronization primitive which can be used by userspace
* to explicitly synchronize GPU commands, can be shared between userspace
* processes, and can be shared between different DRM drivers.
* Their primary use-case is to implement Vulkan fences and semaphores.
[...]
* At it's core, a syncobj is simply a wrapper around a pointer to a struct
* &dma_fence which may be NULL.
And Jason Ekstrand well-summarized dma_fence features in a talk at the Linux Plumbers Conference 2021:
A struct that represents a (potentially future) event:
  • Has a boolean signaled state
  • Has a bunch of useful utility helpers/concepts, such as refcount, callback wait mechanisms, etc.
Provides two guarantees:
  • One-shot: once signaled, it will be signaled forever
  • Finite-time: once exposed, is guaranteed signal in a reasonable amount of time

What does multiple semaphores support mean for Raspberry Pi 4 GPU drivers? For our main purpose, the multiple syncobjs support means that V3DV can submit jobs with more than one wait and signal semaphore. In the kernel space, wait semaphores become explicit job dependencies to wait on before executing the job. Signal semaphores (or post dependencies), in turn, work as fences to be signaled when the job completes its execution, unlocking following jobs that depend on its completion. The multisync support development comprised of many decision-making points and steps summarized as follow:
  • added to the v3d kernel-driver capabilities to handle multiple syncobj;
  • exposed multisync capabilities to the userspace through a generic extension; and
  • reworked synchronization mechanisms of the V3DV driver to benefit from this feature
  • enabled simulator to work with multiple semaphores
  • tested on Vulkan games to verify the correctness and possible performance enhancements.
We decided to refactor parts of the V3D(V) submission design in kernel-space and userspace during this development. We improved job scheduling on V3D-kernel and the V3DV job submission design. We also delivered more accurate synchronizing mechanisms and further updates in the Broadcom Vulkan driver running on Raspberry Pi 4. Therefore, we summarize here changes in the kernel space, describing the previous state of the driver, taking decisions, side improvements, and fixes.

From single to multiple binary in/out syncobjs: Initially, V3D was very limited in the numbers of syncobjs per job submission. V3D job interfaces (CL, CSD, and TFU) only supported one syncobj (in_sync) to be added as an execution dependency and one syncobj (out_sync) to be signaled when a submission completes. Except for CL submission, which accepts two in_syncs: one for binner and another for render job, it didn t change the limited options. Meanwhile in the userspace, the V3DV driver followed alternative paths to meet Vulkan s synchronization and submission framework. It needed to handle multiple wait and signal semaphores, but the V3D kernel-driver interface only accepts one in_sync and one out_sync. In short, V3DV had to fit multiple semaphores into one when submitting every GPU job.

Generic ioctl extension The first decision was how to extend the V3D interface to accept multiple in and out syncobjs. We could extend each ioctl with two entries of syncobj arrays and two entries for their counters. We could create new ioctls with multiple in/out syncobj. But after examining other drivers solutions to extend their submission s interface, we decided to extend V3D ioctls (v3d_cl_submit_ioctl, v3d_csd_submit_ioctl, v3d_tfu_submit_ioctl) by a generic ioctl extension. I found a curious commit message when I was examining how other developers handled the issue in the past: 
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Mar 22 09:23:22 2019 +0000
    drm/i915: Introduce the i915_user_extension_method
    
    An idea for extending uABI inspired by Vulkan's extension chains.
    Instead of expanding the data struct for each ioctl every time we need
    to add a new feature, define an extension chain instead. As we add
    optional interfaces to control the ioctl, we define a new extension
    struct that can be linked into the ioctl data only when required by the
    user. The key advantage being able to ignore large control structs for
    optional interfaces/extensions, while being able to process them in a
    consistent manner.
    
    In comparison to other extensible ioctls, the key difference is the
    use of a linked chain of extension structs vs an array of tagged
    pointers. For example,
    
    struct drm_amdgpu_cs_chunk  
    	__u32		chunk_id;
        __u32		length_dw;
        __u64		chunk_data;
     ;
[...]
So, inspired by amdgpu_cs_chunk and i915_user_extension, we opted to extend the V3D interface through a generic interface. After applying some suggestions from Iago Toral (Igalia) and Daniel Vetter, we reached the following struct: 
struct drm_v3d_extension  
	__u64 next;
	__u32 id;
#define DRM_V3D_EXT_ID_MULTI_SYNC		0x01
	__u32 flags; /* mbz */
 ;
This generic extension has an id to identify the feature/extension we are adding to an ioctl (that maps the related struct type), a pointer to the next extension, and flags (if needed). Whenever we need to extend the V3D interface again for another specific feature, we subclass this generic extension into the specific one instead of extending ioctls indefinitely.

Multisync extension For the multiple syncobjs extension, we define a multi_sync extension struct that subclasses the generic extension struct. It has arrays of in and out syncobjs, the respective number of elements in each of them, and a wait_stage value used in CL submissions to determine which job needs to wait for syncobjs before running. 
struct drm_v3d_multi_sync  
	struct drm_v3d_extension base;
	/* Array of wait and signal semaphores */
	__u64 in_syncs;
	__u64 out_syncs;
	/* Number of entries */
	__u32 in_sync_count;
	__u32 out_sync_count;
	/* set the stage (v3d_queue) to sync */
	__u32 wait_stage;
	__u32 pad; /* mbz */
 ;
And if a multisync extension is defined, the V3D driver ignores the previous interface of single in/out syncobjs. Once we had the interface to support multiple in/out syncobjs, v3d kernel-driver needed to handle it. As V3D uses the DRM scheduler for job executions, changing from single syncobj to multiples is quite straightforward. V3D copies from userspace the in syncobjs and uses drm_syncobj_find_fence()+ drm_sched_job_add_dependency() to add all in_syncs (wait semaphores) as job dependencies, i.e. syncobjs to be checked by the scheduler before running the job. On CL submissions, we have the bin and render jobs, so V3D follows the value of wait_stage to determine which job depends on those in_syncs to start its execution. When V3D defines the last job in a submission, it replaces dma_fence of out_syncs with the done_fence from this last job. It uses drm_syncobj_find() + drm_syncobj_replace_fence() to do that. Therefore, when a job completes its execution and signals done_fence, all out_syncs are signaled too.

Other improvements to v3d kernel driver This work also made possible some improvements in the original implementation. Following Iago s suggestions, we refactored the job s initialization code to allocate memory and initialize a job in one go. With this, we started to clean up resources more cohesively, clearly distinguishing cleanups in case of failure from job completion. We also fixed the resource cleanup when a job is aborted before the DRM scheduler arms it - at that point, drm_sched_job_arm() had recently been introduced to job initialization. Finally, we prepared the semaphore interface to implement timeline syncobjs in the future.

Going Up The patchset that adds multiple syncobjs support and improvements to V3D is available here and comprises four patches:
  • drm/v3d: decouple adding job dependencies steps from job init
  • drm/v3d: alloc and init job in one shot
  • drm/v3d: add generic ioctl extension
  • drm/v3d: add multiple syncobjs support
After extending the V3D kernel interface to accept multiple syncobjs, we worked on V3DV to benefit from V3D multisync capabilities. In the next post, I will describe a little of this work.

Utkarsh Gupta: FOSS Activites in April 2022

Here s my (thirty-first) monthly but brief update about the activities I ve done in the F/L/OSS world.

Debian
This was my 40th month of actively contributing to Debian. I became a DM in late March 2019 and a DD on Christmas 19! \o/ There s a bunch of things I did this month but mostly non-technical, now that DC22 is around the corner. Here are the things I did:

Debian Uploads
  • Helped Andrius w/ FTBFS for php-text-captcha, reported via #977403.
    • I fixed the samed in Ubuntu a couple of months ago and they copied over the patch here.

Other $things:
  • Volunteering for DC22 Content team.
  • Leading the Bursary team w/ Paulo.
  • Answering a bunch of questions of referees and attendees around bursary.
  • Being an AM for Arun Kumar, process #1024.
  • Mentoring for newcomers.
  • Moderation of -project mailing list.

Ubuntu
This was my 15th month of actively contributing to Ubuntu. Now that I joined Canonical to work on Ubuntu full-time, there s a bunch of things I do! \o/ I mostly worked on different things, I guess. I was too lazy to maintain a list of things I worked on so there s no concrete list atm. Maybe I ll get back to this section later or will start to list stuff from the fall, as I was doing before. :D

Debian (E)LTS
Debian Long Term Support (LTS) is a project to extend the lifetime of all Debian stable releases to (at least) 5 years. Debian LTS is not handled by the Debian security team, but by a separate group of volunteers and companies interested in making it a success. And Debian Extended LTS (ELTS) is its sister project, extending support to the Jessie release (+2 years after LTS support). This was my thirty-first month as a Debian LTS and twentieth month as a Debian ELTS paid contributor.
I worked for 23.25 hours for LTS and 20.00 hours for ELTS.

LTS CVE Fixes and Announcements:
  • Issued DLA 2976-1, fixing CVE-2022-1271, for gzip.
    For Debian 9 stretch, these problems have been fixed in version 1.6-5+deb9u1.
  • Issued DLA 2977-1, fixing CVE-2022-1271, for xz-utils.
    For Debian 9 stretch, these problems have been fixed in version 5.2.2-1.2+deb9u1.
  • Working on src:tiff and src:mbedtls to fix the issues, still waiting for more issues to be reported, though.
  • Looking at src:mutt CVEs. Haven t had the time to complete but shall roll out next month.

ELTS CVE Fixes and Announcements:
  • Issued ELA 593-1, fixing CVE-2022-1271, for gzip.
    For Debian 8 jessie, these problems have been fixed in version 1.6-4+deb8u1.
  • Issued ELA 594-1, fixing CVE-2022-1271, for xz-utils.
    For Debian 8 jessie, these problems have been fixed in version 5.1.1alpha+20120614-2+deb8u1.
  • Issued ELA 598-1, fixing CVE-2019-16935, CVE-2021-3177, and CVE-2021-4189, for python2.7.
    For Debian 8 jessie, these problems have been fixed in version 2.7.9-2-ds1-1+deb8u9.
  • Working on src:tiff and src:beep to fix the issues, still waiting for more issues to be reported for src:tiff and src:beep is a bit of a PITA, though. :)

Other (E)LTS Work:
  • Triaged gzip, xz-utils, tiff, beep, python2.7, python-django, and libgit2,
  • Signed up to be a Freexian Collaborator! \o/
  • Read through some bits around that.
  • Helped and assisted new contributors joining Freexian.
  • Answered questions (& discussions) on IRC (#debian-lts and #debian-elts).
  • General and other discussions on LTS private and public mailing list.
  • Attended monthly Debian meeting. Held on Jitsi this month.

Debian LTS Survey I ve spent 18 hours on the LTS survey on the following bits:
  • Rolled out the announcement. Started the survey.
  • Answered a bunch of queries, people asked via e-mail.
  • Looked at another bunch of tickets: https://salsa.debian.org/freexian-team/project-funding/-/issues/23.
  • Sent a reminder and fixed a few things here and there.
  • Gave a status update during the meeting.
  • Extended the duration of the survey.
Until next time.
:wq for today.

9 May 2022

Robert McQueen: Evolving a strategy for 2022 and beyond

As a board, we have been working on several initiatives to make the Foundation a better asset for the GNOME Project. We re working on a number of threads in parallel, so I wanted to explain the big picture a bit more to try and connect together things like the new ED search and the bylaw changes. We re all here to see free and open source software succeed and thrive, so that people can be be truly empowered with agency over their technology, rather than being passive consumers. We want to bring GNOME to as many people as possible so that they have computing devices that they can inspect, trust, share and learn from. In previous years we ve tried to boost the relevance of GNOME (or technologies such as GTK) or solicit donations from businesses and individuals with existing engagement in FOSS ideology and technology. The problem with this approach is that we re mostly addressing people and organisations who are already supporting or contributing FOSS in some way. To truly scale our impact, we need to look to the outside world, build better awareness of GNOME outside of our current user base, and find opportunities to secure funding to invest back into the GNOME project. The Foundation supports the GNOME project with infrastructure, arranging conferences, sponsoring hackfests and travel, design work, legal support, managing sponsorships, advisory board, being the fiscal sponsor of GNOME, GTK, Flathub and we will keep doing all of these things. What we re talking about here are additional ways for the Foundation to support the GNOME project we want to go beyond these activities, and invest into GNOME to grow its adoption amongst people who need it. This has a cost, and that means in parallel with these initiatives, we need to find partners to fund this work. Neil has previously talked about themes such as education, advocacy, privacy, but we ve not previously translated these into clear specific initiatives that we would establish in addition to the Foundation s existing work. This is all a work in progress and we welcome any feedback from the community about refining these ideas, but here are the current strategic initiatives the board is working on. We ve been thinking about growing our community by encouraging and retaining diverse contributors, and addressing evolving computing needs which aren t currently well served on the desktop. Initiative 1. Welcoming newcomers. The community is already spending a lot of time welcoming newcomers and teaching them the best practices. Those activities are as time consuming as they are important, but currently a handful of individuals are running initiatives such as GSoC, Outreachy and outreach to Universities. These activities help bring diverse individuals and perspectives into the community, and helps them develop skills and experience of collaborating to create Open Source projects. We want to make those efforts more sustainable by finding sponsors for these activities. With funding, we can hire people to dedicate their time to operating these programs, including paid mentors and creating materials to support newcomers in future, such as developer documentation, examples and tutorials. This is the initiative that needs to be refined the most before we can turn it into something real. Initiative 2: Diverse and sustainable Linux app ecosystem. I spoke at the Linux App Summit about the work that GNOME and Endless has been supporting in Flathub, but this is an example of something which has a great overlap between commercial, technical and mission-based advantages. The key goal here is to improve the financial sustainability of participating in our community, which in turn has an impact on the diversity of who we can expect to afford to enter and remain in our community. We believe the existence of this is critically important for individual developers and contributors to unlock earning potential from our ecosystem, through donations or app sales. In turn, a healthy app ecosystem also improves the usefulness of the Linux desktop as a whole for potential users. We believe that we can build a case for commercial vendors in the space to join an advisory board alongside with GNOME, KDE, etc to input into the governance and contribute to the costs of growing Flathub. Initiative 3: Local-first applications for the GNOME desktop. This is what Thib has been starting to discuss on Discourse, in this thread. There are many different threats to free access to computing and information in today s world. The GNOME desktop and apps need to give users convenient and reliable access to technology which works similarly to the tools they already use everyday, but keeps them and their data safe from surveillance, censorship, filtering or just being completely cut off from the Internet. We believe that we can seek both philanthropic and grant funding for this work. It will make GNOME a more appealing and comprehensive offering for the many people who want to protect their privacy. The idea is that these initiatives all sit on the boundary between the GNOME community and the outside world. If the Foundation can grow and deliver these kinds of projects, we are reaching to new people, new contributors and new funding. These contributions and investments back into GNOME represent a true win-win for the newcomers and our existing community. (Originally posted to GNOME Discourse, please feel free to join the discussion there.)

Russ Allbery: remctl 3.18

remctl is a simple RPC mechanism using Kerberos GSS-API authentication (or SSH authentication). The primary change in this release, and the reason for the release, is to add support for PCRE2, the latest version of the Perl-Compatible Regular Expression library, since PCRE1 is now deprecated. This release also improves some documentation, marks the allocation functions in the C client library with deallocation functions for GCC 11, and fixes some issues with the Python and Ruby bindings that were spotted by Ken Dreyer, as well as the normal update of portability support. I still do plan to move the language bindings into separate packages, since this will make it easier to upload them to their per-language module repositories and that, in turn, will make them easier to use, but this version doesn't have those changes. I wanted to flush the portability changes and PCRE update out first before starting that project. You can get the latest version from the remctl distribution page.

Russ Allbery: rra-c-util 10.2

rra-c-util is my collection of utility functions, mostly but not entirely for C, that I use with my various software releases. There are two major changes in this release. The first is Autoconf support for PCRE2, the new version of the Perl-Compatible Regular Expression library (PCRE1 is now deprecated), which was the motivation for a new release. The second is a huge update to the Perl formatting rules due to lots of work by Julien LIE for INN. This release also tags deallocation functions, similar to the change mentioned for C TAP Harness 4.8, for all the utility libraries provided by rra-c-util, and fixes an issue with the systemd support. You can get the latest version from the rra-c-util distribution page.

Russ Allbery: C TAP Harness 4.8

C TAP Harness is my C implementation of the Perl "Test Anything Protocol" test suite framework. It includes test runner and libraries for both C and shell. This is mostly a cleanup release to resync with other utility libraries. It does fix an installation problem by managing symlinks correctly, and adds support for GCC 11's new deallocation warnings. The latter is a rather interesting new GCC feature. There is a Red Hat blog post about the implementation with more details, but the short version is that the __malloc__ attribute can now take an argument that specifies the function that should be used to deallocate the allocated object. GCC 11 and later can use that information to catch some deallocation bugs, such as deallocating things with the wrong function. You can get the latest version from the C TAP Harness distribution page.

8 May 2022

Thorsten Alteholz: My Debian Activities in April 2022

FTP master This month I accepted 186 and rejected 26 packages. The overall number of packages that got accepted was 188. Debian LTS This was my ninety-fourth month that I did some work for the Debian LTS initiative, started by Raphael Hertzog at Freexian. This month my all in all workload has been 40h. During that time I did LTS and normal security uploads of: Further I worked on libvirt, the dependency problems in unstable have been resolved and fixing in other releases can continue. I also continued to work on security support for golang packages. Last but not least I did some days of frontdesk duties. Debian ELTS This month was the forty-siyth ELTS month. During my allocated time I uploaded: Last but not least I did some days of frontdesk duties. Debian Printing This month I uploaded new upstream versions or improved packaging of: As I already became the maintainer of usb-modeswitch I also adopted usb-modeswitch-data Debian Astro Unfortunately I didn t do anything for this group, but in May I will upload a new version of openvlbi and several indi-3rdparty packages. Other stuff Last but not least I uploaded several new upstream version of golang packages but not before checking with ratt that all dependencies still work.

6 May 2022

Dirk Eddelbuettel: RProtoBuf 0.4.19 on CRAN: Updates

A new release 0.4.19 of RProtoBuf arrived on CRAN earlier today. RProtoBuf provides R with bindings for the Google Protocol Buffers ( ProtoBuf ) data encoding and serialization library used and released by Google, and deployed very widely in numerous projects as a language and operating-system agnostic protocol. This release contains a pull request contribution by Michael Chirico to add support for the TextFormat API, a minor maintenance fix ensuring (standard) string are referenced as std::string to avoid a hickup on Arch builds, some repo updates, plus reporting of (package and library) versions on startup. The following section from the NEWS.Rd file has more details.

Changes in RProtoBuf version 0.4.19 (2022-05-06)
  • Small cleanups to repository
  • Raise minimum Protocol Buffers version to 3.3 (closes #83)
  • Update package version display, added to startup message
  • Expose TextFormat API (Michael Chirico in #88 closing #87)
  • Add missing explicit std:: on seven string instances in one file (closes #89)

Thanks to my CRANberries, there is a diff to the previous release. The RProtoBuf page has copies of the (older) package vignette, the quick overview vignette, and the pre-print of our JSS paper. Questions, comments etc should go to the GitHub issue tracker off the GitHub repo. If you like this or other open-source work I do, you can now sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Antoine Beaupr : Wallabako 1.4.0 released

I don't particularly like it when people announce their personal projects on their blog, but I'm making an exception for this one, because it's a little special for me. You see, I have just released Wallabako 1.4.0 (and a quick, mostly irrelevant 1.4.1 hotfix) today. It's the first release of that project in almost 3 years (the previous was 1.3.1, before the pandemic). The other reason I figured I would mention it is that I have almost never talked about Wallabako on this blog at all, so many of my readers probably don't even know I sometimes meddle with in Golang which surprises even me sometimes.

What's Wallabako Wallabako is a weird little program I designed to read articles on my E-book reader. I use it to spend less time on the computer: I save articles in a read-it-later app named Wallabag (hosted by a generous friend), and then Wallabako connects to that app, downloads an EPUB version of the book, and then I can read it on the device directly. When I'm done reading the book, Wallabako notices and sets the article as read in Wallabag. I also set it to delete the book locally, but you can actually configure to keep those books around forever if you feel like it. Wallabako supports syncing read status with the built-in Kobo interface (called "Nickel"), Koreader and Plato. I happen to use Koreader for everything nowadays, but it should work equally well on the others. Wallabako is actually setup to be started by udev when there's a connection change detected by the kernel, which is kind of a gross hack. It's clunky, but actually works and I thought for a while about switching to something else, but it's really the easiest way to go, and that requires the less interaction by the user.

Why I'm (still) using it I wrote Wallabako because I read a lot of articles on the internet. It's actually most of my readings. I read about 10 books a year (which I don't think is much), but I probably read more in terms of time and pages in Wallabag. I haven't actually made the math, but I estimate I spend at least double the time reading articles than I spend reading books. If I wouldn't have Wallabag, I would have hundreds of tabs open in my web browser all the time. So at least that problem is easily solved: throw everything in Wallabag, sort and read later. If I wouldn't have Wallabako however, I would be either spend that time reading on the computer -- which I prefer to spend working on free software or work -- or on my phone -- which is kind of better, but really cramped. I had stopped (and developing) Wallabako for a while, actually, Around 2019, I got tired of always read those technical articles (basically work stuff!) at home. I realized I was just not "reading" (as in books! fiction! fun stuff!) anymore, at least not as much as I wanted. So I tried to make this separation: the ebook reader is for cool book stuff. The rest is work. But because I had the Wallabag Android app on my phone and tablet, I could still read those articles there, which I thought was pretty neat. But that meant that I was constantly looking at my phone, which is something I'm generally trying to avoid, as it sets a bad example for the kids (small and big) around me. Then I realized there was one stray ebook reader lying around at home. I had recently bought a Kobo Aura HD to read books, and I like that device. And it's going to stay locked down to reading books. But there's still that old battered Kobo Glo HD reader lying around, and I figured I could just borrow it to read Wallabag articles.

What is this new release But oh boy that was a lot of work. Wallabako was kind of a mess: it was using the deprecated go dep tool, which lost the battle with go mod. Cross-compilation was broken for older devices, and I had to implement support for Koreader.

go mod So I had to learn go mod. I'm still not sure I got that part right: LSP is yelling at me because it can't find the imports, and I'm generally just "YOLO everythihng" every time I get anywhere close to it. That's not the way to do Go, in general, and not how I like to do it either. But I guess that, given time, I'll figure it out and make it work for me. It certainly works now. I think.

Cross compilation The hard part was different. You see, Nickel uses SQLite to store metadata about books, so Wallabako actually needs to tap into that SQLite database to propagate read status. Originally, I just linked against some sqlite3 library I found lying around. It's basically a wrapper around the C-based SQLite and generally works fine. But that means you actually link your Golang program against a C library. And that's when things get a little nutty. If you would just build Wallabag naively, it would fail when deployed on the Kobo Glo HD. That's because the device runs a really old kernel: the prehistoric Linux kobo 2.6.35.3-850-gbc67621+ #2049 PREEMPT Mon Jan 9 13:33:11 CST 2017 armv7l GNU/Linux. That was built in 2017, but the kernel was actually released in 2010, a whole 5 years before the Glo HD was released, in 2015 which is kind of outrageous. and yes, that is with the latest firmware release. My bet is they just don't upgrade the kernel on those things, as the Glo was probably bought around 2017... In any case, the problem is we are cross-compiling here. And Golang is pretty good about cross-compiling, but because we have C in there, we're actually cross-compiling with "CGO" which is really just Golang with a GCC backend. And that's much, much harder to figure out because you need to pass down flags into GCC and so on. It was a nightmare. That's until I found this outrageous "little" project called modernc.org/sqlite. What that thing does (with a hefty does of dependencies that would make any Debian developer recoil in horror) is to transpile the SQLite C source code to Golang. You read that right: it rewrites SQLite in Go. On the fly. It's nuts. But it works. And you end up with a "pure go" program, and that thing compiles much faster and runs fine on older kernel. I still wasn't sure I wanted to just stick with that forever, so I kept the old sqlite3 code around, behind a compile-time tag. At the top of the nickel_modernc.go file, there's this magic string: 
//+build !sqlite3
And at the top of nickel_sqlite3.go file, there's this magic string: 
//+build sqlite3
So now, by default, the modernc file gets included, but if I pass --tags sqlite3 to the Go compiler (to go install or whatever), it will actually switch to the other implementation. Pretty neat stuff.

Koreader port The last part was something I was hesitant in doing for a long time, but that turned out to be pretty easy. I have basically switch to using Koreader to read everything. Books, PDF, everything goes through it. I really like that it stores its metadata in sidecar files: I synchronize all my books with Syncthing which means I can carry my read status, annotations and all that stuff without having to think about it. (And yes, I installed Syncthing on my Kobo.) The koreader.go port was less than 80 lines, and I could even make a nice little test suite so that I don't have to redeploy that thing to the ebook reader at every code iteration. I had originally thought I should add some sort of graphical interface in Koreader for Wallabako as well, and had requested that feature upstream. Unfortunately (or fortunately?), they took my idea and just ran with it. Some courageous soul actually wrote a full Wallabag plugin for koreader, in Lua of course. Compared to the Wallabako implementation however, the koreader plugin is much slower, probably because it downloads articles serially instead of concurrently. It is, however, much more usable as the user is given a visible feedback of the various steps. I still had to enable full debugging to diagnose a problem (which was that I shouldn't have a trailing slash, and that some special characters don't work in passwords). It's also better to write the config file with a normal text editor, over SSH or with the Kobo mounted to your computer instead of typing those really long strings over the kobo. There's no sample config file which makes that harder but a workaround is to save the configuration with dummy values and fix them up after. Finally I also found the default setting ("Remotely delete finished articles") really dangerous as it can basically lead to data loss (Wallabag article being deleted!) for an unsuspecting user... So basically, I started working on Wallabag again because the koreader implementation of their Wallabag client was not up to spec for me. It might be good enough for you, but I guess if you like Wallabako, you should thank the koreader folks for their sloppy implementation, as I'm now working again on Wallabako.

Actual release notes Those are the actual release notes for 1.4.0.
Ship a lot of fixes that have accumulated in the 3 years since the last release. Features:
  • add timestamp and git version to build artifacts
  • cleanup and improve debugging output
  • switch to pure go sqlite implementation, which helps
  • update all module dependencies
  • port to wallabago v6
  • support Plato library changes from 0.8.5+
  • support reading koreader progress/read status
  • Allow containerized builds, use gomod and avoid GOPATH hell
  • overhaul Dockerfile
  • switch to go mod
Documentation changes:
  • remove instability warning: this works well enough
  • README: replace branch name master by main in links
  • tweak mention of libreoffice to clarify concern
  • replace "kobo" references by "nickel" where appropriate
  • make a section about related projects
  • mention NickelMenu
  • quick review of the koreader implementation
Bugfixes:
  • handle errors in http request creation
  • Use OutputDir configuration instead of hardcoded wallabako paths
  • do not noisily fail if there's no entry for book in plato
  • regression: properly detect read status again after koreader (or plato?) support was added

How do I use this?
This is amazing. I can't believe someone did something that awesome. I want to cover you with gold and Tesla cars and fresh water.
You're weird please stop. But if you want to use Wallabako, head over to the README file which has installation instructions. It basically uses a hack in Kobo e-readers that will happily overwrite their root filesystem as soon as you drop this file named KoboRoot.tgz in the .kobo directory of your e-reader. Note that there is no uninstall procedure and it messes with the reader's udev configuration (to trigger runs on wifi connect). You'll also need to create a JSON configuration file and configure a client in Wallabag. And if you're looking for Wallabag hosting, Wallabag.it offers a 14-day free trial. You can also, obviously, host it yourself. Which is not the case for Pocket, even years after Mozilla bought the company. All this wouldn't actually be necessary if Pocket was open-source because Nickel actually ships with a Pocket client. Shame on you, Mozilla. But you still make an awesome browser, so keep doing that.

Dirk Eddelbuettel: RQuantLib 0.4.16 on CRAN: Small Updates

A new release 0.4.16 of RQuantLib arrived at CRAN earlier today, and has been uploaded to Debian as well. QuantLib is a very comprehensice free/open-source library for quantitative finance; RQuantLib connects it to the R environment and language. The release of RQuantLib comes agaain about four months after the previous release, and brings a a few small updates for daycounters, all thanks to Kai Lin, plus a small parameter change to avoid an error in an example, and small updates to the Docker files.

Changes in RQuantLib version 0.4.16 (2022-05-05)
  • Documentationn for daycounters was updated and extended (Kai Lin)
  • Deprecated daycounters were approtiately updated (Kai Lin)
  • One example parameterization was changed to avoid error (Dirk)
  • The Docker files were updated

Courtesy of my CRANberries, there is also a diffstat report for the this release. As always, more detailed information is on the RQuantLib page. Questions, comments etc should go to the new rquantlib-devel mailing list. Issue tickets can be filed at the GitHub repo. If you like this or other open-source work I do, you can now sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

5 May 2022

Reproducible Builds: Reproducible Builds in April 2022

Welcome to the April 2022 report from the Reproducible Builds project! In these reports, we try to summarise the most important things that we have been up to over the past month. If you are interested in contributing to the project, please take a few moments to visit our Contribute page on our website.

News Cory Doctorow published an interesting article this month about the possibility of Undetectable backdoors for machine learning models. Given that machine learning models can provide unpredictably incorrect results, Doctorow recounts that there exists another category of adversarial examples that comprise a gimmicked machine-learning input that, to the human eye, seems totally normal but which causes the ML system to misfire dramatically that permit the possibility of planting undetectable back doors into any machine learning system at training time .
Chris Lamb published two supporter spotlights on our blog: the first about Amateur Radio Digital Communications (ARDC) and the second about the Google Open Source Security Team (GOSST).
Piergiorgio Ladisa, Henrik Plate, Matias Martinez and Olivier Barais published a new academic paper titled A Taxonomy of Attacks on Open-Source Software Supply Chains (PDF):
This work proposes a general taxonomy for attacks on open-source supply chains, independent of specific programming languages or ecosystems, and covering all supply chain stages from code contributions to package distribution. Taking the form of an attack tree, it covers 107 unique vectors, linked to 94 real-world incidents, and mapped to 33 mitigating safeguards.

Elsewhere in academia, Ly Vu Duc published his PhD thesis. Titled Towards Understanding and Securing the OSS Supply Chain (PDF), Duc s abstract reads as follows:
This dissertation starts from the first link in the software supply chain, developers . Since many developers do not update their vulnerable software libraries, thus exposing the user of their code to security risks. To understand how they choose, manage and update the libraries, packages, and other Open-Source Software (OSS) that become the building blocks of companies completed products consumed by end-users, twenty-five semi-structured interviews were conducted with developers of both large and small-medium enterprises in nine countries. All interviews were transcribed, coded, and analyzed according to applied thematic analysis

Upstream news Filippo Valsorda published an informative blog post recently called How Go Mitigates Supply Chain Attacks outlining the high-level features of the Go ecosystem that helps prevent various supply-chain attacks.
There was new/further activity on a pull request filed against openssl by Sebastian Andrzej Siewior in order to prevent saved CFLAGS (which may contain the -fdebug-prefix-map=<PATH> flag that is used to strip an arbitrary the build path from the debug info if this information remains recorded then the binary is no longer reproducible if the build directory changes.

Events The Linux Foundation s SupplyChainSecurityCon, will take place June 21st 24th 2022, both virtually and in Austin, Texas. Long-time Reproducible Builds and openSUSE contributor Bernhard M. Wiedemann learned that he had his talk accepted, and will speak on Reproducible Builds: Unexpected Benefits and Problems on June 21st.
There will be an in-person Debian Reunion in Hamburg, Germany later this year, taking place from 23 30 May. Although this is a Debian event, there will be some folks from the broader Reproducible Builds community and, of course, everyone is welcome. Please see the event page on the Debian wiki for more information. 41 people have registered so far, and there s approx 10 on-site beds still left.
The minutes and logs from our April 2022 IRC meeting have been published. In case you missed this one, our next IRC meeting will take place on May 31st at 15:00 UTC on #reproducible-builds on the OFTC network.

Debian Roland Clobus wrote another in-depth status update about the status of live Debian images, summarising the current situation that all major desktops build reproducibly with bullseye, bookworm and sid, including the Cinnamon desktop on bookworm and sid, but at a small functionality cost: 14 words will be incorrectly abbreviated . This work incorporated:
  • Reporting an issue about unnecessarily modified timestamps in the daily Debian installer images. [ ]
  • Reporting a bug against the debian-installer: in order to use a suitable kernel version. (#1006800)
  • Reporting a bug in: texlive-binaries regarding the unreproducible content of .fmt files. (#1009196)
  • Adding hacks to make the Cinnamon desktop image reproducible in bookworm and sid. [ ]
  • Added a script to rebuild a live-build ISO image from a given timestamp. [
  • etc.
On our mailing list, Venkata Pyla started a thread on the Debian debconf cache is non-reproducible issue while creating system images and Vagrant Cascadian posted an excellent summary of the reproducibility status of core package sets in Debian and solicited for similar information from other distributions.
Lastly, 122 reviews of Debian packages were added, 44 were updated and 193 were removed this month adding to our extensive knowledge about identified issues. A number of issue types have been updated as well, including timestamps_generated_by_hevea, randomness_in_ocaml_preprocessed_files, build_path_captured_in_emacs_el_file, golang_compiler_captures_build_path_in_binary and build_path_captured_in_assembly_objects,

Other distributions Happy birthday to GNU Guix, which recently turned 10 years old! People have been sharing their stories, in which reproducible builds and bootstrappable builds are a recurring theme as a feature important to its users and developers. The experiences are available on the GNU Guix blog as well as a post on fossandcrafts.org
In openSUSE, Bernhard M. Wiedemann posted his usual monthly reproducible builds status report.

Upstream patches The Reproducible Builds project detects, dissects and attempts to fix as many currently-unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including:

diffoscope diffoscope is our in-depth and content-aware diff utility. Not only can it locate and diagnose reproducibility issues, it can provide human-readable diffs from many kinds of binary formats. This month, Chris Lamb prepared and uploaded versions 210 and 211 to Debian unstable, as well as noticed that some Python .pyc files are reported as data, so we should support .pyc as a fallback filename extension [ ]. In addition, Mattia Rizzolo disabled the Gnumeric tests in Debian as the package is not currently available [ ] and dropped mplayer from Build-Depends too [ ]. In addition, Mattia fixed an issue to ensure that the PATH environment variable is properly modified for all actions, not just when running the comparator. [ ]

Testing framework The Reproducible Builds project runs a significant testing framework at tests.reproducible-builds.org, to check packages and other artifacts for reproducibility. This month, the following changes were made:
  • Daniel Golle:
    • Prefer a different solution to avoid building all OpenWrt packages; skip packages from optional community feeds. [ ]
  • Holger Levsen:
    • Detect Python deprecation warnings in the node health check. [ ]
    • Detect failure to build the Debian Installer. [ ]
  • Mattia Rizzolo:
    • Install disorderfs for building OpenWrt packages. [ ]
  • Paul Spooren (OpenWrt-related changes):
    • Don t build all packages whilst the core packages are not yet reproducible. [ ]
    • Add a missing RUN directive to node_cleanup. [ ]
    • Be less verbose during a toolchain build. [ ]
    • Use disorderfs for rebuilds and update the documentation to match. [ ][ ][ ]
  • Roland Clobus:
    • Publish the last reproducible Debian ISO image. [ ]
    • Use the rebuild.sh script from the live-build package. [ ]
Lastly, node maintenance was also performed by Holger Levsen [ ][ ].
If you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

Bits from Debian: Google Platinum Sponsor of DebConf22

Googlelogo We are very pleased to announce that Google has committed to support DebConf22 as a Platinum sponsor. This is the third year in a row that Google is sponsoring The Debian Conference with the higher tier! Google is one of the largest technology companies in the world, providing a wide range of Internet-related services and products as online advertising technologies, search, cloud computing, software, and hardware. Google has been supporting Debian by sponsoring DebConf since more than ten years, and is also a Debian partner sponsoring parts of Salsa's continuous integration infrastructure within Google Cloud Platform. With this additional commitment as Platinum Sponsor for DebConf22, Google contributes to make possible our annual conference, and directly supports the progress of Debian and Free Software helping to strengthen the community that continues to collaborate on Debian projects throughout the rest of the year. Thank you very much Google, for your support of DebConf22! Become a sponsor too! DebConf22 will take place from July 17th to 24th, 2022 at the Innovation and Training Park (ITP) in Prizren, Kosovo, and will be preceded by DebCamp, from July 10th to 16th. And DebConf22 is still accepting sponsors! Interested companies and organizations may contact the DebConf team through sponsors@debconf.org, and visit the DebConf22 website at https://debconf22.debconf.org/sponsors/become-a-sponsor. DebConf22 banner open registration

3 May 2022

Steve Kemp: A plea for books ..

Recently I've been getting much more interested in the "retro" computers of my youth, partly because I've been writing crazy code in Z80 assembly-language, and partly because I've been preparing to introduce our child to his first computer: I've got a few books, books I've hoarded for 30+ years, but I'd love to collect some more. So here's my request: I'd be happy to pay 5-10 each for any book I don't yet own, and I'd also be more than happy to cover the cost of postage to Finland. I'd be particularly pleased to see anything from Melbourne House, and while low-level is best, the coding-books from Usbourne (The Mystery Of Silver Mountain, etc, etc) wouldn't go amiss either. I suspect most people who have collected and kept these wouldn't want to part with them, but just in case ..

Gunnar Wolf: Using a RPi as a display adapter

Almost ten months ago, I mentioned on this blog I bought an ARM laptop, which is now my main machine while away from home a Lenovo Yoga C630 13Q50. Yes, yes, I am still not as much away from home as I used to before, as this pandemic is still somewhat of a thing, but I do move more. My main activity in the outside world with my laptop is teaching. I teach twice a week, and well, having a display for my slides and for showing examples in the terminal and such is a must. However, as I said back in August, one of the hardware support issues for this machine is: 
No HDMI support via the USB-C displayport. While I don t expect
to go to conferences or even classes in the next several months,
I hope this can be fixed before I do. It s a potential important
issue for me.
It has sadly not yet been solved While many things have improved since kernel 5.12 (the first I used), the Device Tree does not yet hint at where external video might sit. So, I went to the obvious: Many people carry different kinds of video adaptors I carry a slightly bulky one: A RPi3 For two months already (time flies!), I had an ugly contraption where the RPi3 connected via Ethernet and displayed a VNC client, and my laptop had a VNC server. Oh, but did I mention My laptop works so much better with Wayland than with Xorg that I switched, and am now a happy user of the Sway compositor (a drop-in replacement for the i3 window manager). It is built over WLRoots, which is a great and (relatively) simple project, but will thankfully not carry some of Gnome or KDE s ideas not even those I d rather have. So it took a bit of searching; I was very happy to find WayVNC, a VNC server for wlroot-sbased Wayland compositors. I launched a second Wayland, to be able to have my main session undisturbed and present only a window from it. Only that VNC is slow and laggy, and sometimes awkward. So I kept searching for something better. And something better is, happily, what I was finally able to do! In the laptop, I am using wf-recorder to grab an area of the screen and funnel it into a V4L2 loopback device (which allows it to be used as a camera, solving the main issue with grabbing parts of a Wayland screen): 
/usr/bin/wf-recorder -g '0,32 960x540' -t --muxer=v4l2 --codec=rawvideo --pixelformat=yuv420p --file=/dev/video10
(yes, my V4L2Loopback device is set to /dev/video10). You will note I m grabbing a 960 540 rectangle, which is the top of my screen (1920x1080) minus the Waybar. I think I ll increase it to 960 720, as the projector to which I connect the Raspberry has a 4 3 output. After this is sent to /dev/video10, I tell ffmpeg to send it via RTP to the fixed address of the Raspberry: 
/usr/bin/ffmpeg -i /dev/video10 -an -f rtp -sdp_file /tmp/video.sdp rtp://10.0.0.100:7000/
Yes, some uglier things happen here. You will note /tmp/video.sdp is created in the laptop itself; this file describes the stream s metadata so it can be used from the client side. I cheated and copied it over to the Raspberry, doing an ugly hardcode along the way: 
user@raspi:~ $ cat video.sdp
v=0
o=- 0 0 IN IP4 127.0.0.1
s=No Name
c=IN IP4 10.0.0.100
t=0 0
a=tool:libavformat 58.76.100
m=video 7000 RTP/AVP 96
b=AS:200
a=rtpmap:96 MP4V-ES/90000
a=fmtp:96 profile-level-id=1
People familiar with RTP will scold me: How come I m streaming to the unicast client address? I should do it to an address in the 224.0.0.0 239.0.0.0 range. And it worked, sometimes. I switched over to 10.0.0.100 because it works, basically always Finally, upon bootup, I have configured NoDM to start a session with the user user, and dropped the following in my user s .xsession: 
setterm -blank 0 -powersave off -powerdown 0
xset s off
xset -dpms
xset s noblank
mplayer -msglevel all=1 -fs /home/usuario/video.sdp
Anyway, as a result, my students are able to much better follow the pace of my presentation, and I m able to do some tricks better (particularly when it requires quick reaction times, as often happens when dealing with concurrency and such issues). Oh, and of course in case it s of interest to anybody, knowing that SD cards are all but reliable in the long run, I wrote a vmdb2 recipe to build the images. You can grab it here; it requires some local files to be present to be built some are the ones I copied over above, and the other ones are surely of no interest to you (such as my public ssh key or such :-] ) What am I still missing? (read: Can you help me with some ideas? ) Of course, this is a blog post published to brag about my stuff, but also to serve me as persistent memory in case I need to recreate this

1 May 2022

Paul Wise: FLOSS Activities April 2022

Focus This month I didn't have any particular focus. I just worked on issues in my info bubble.

Changes

Issues

Review
  • Spam: reported 33 Debian mailing list posts
  • Debian wiki: RecentChanges for the month
  • Debian BTS usertags: changes for the month
  • Debian screenshots:

Administration
  • Debian wiki: unblock IP addresses, approve accounts

Communication

Sponsors The libpst, gensim, SPTAG work was sponsored. All other work was done on a volunteer basis.

29 April 2022

Jonathan Dowland: hyperlinked PDF planner

The Year page The Year page
A day page A day page
I've been having reasonable success with time blocking, a technique I learned from Cal Newport's writings, in particular Deep Work. I'd been doing it on paper for a while, but I wanted to try and move to a digital solution. There's a cottage industry of people making (and selling) various types of diary and planner as PDF files for use on tablets such as the Remarkable. Some of these use PDF hyperlinks to greatly improve navigating around. This one from Clou Media is particularly good, but I found that I wanted something slightly different from what I could find out there, so I decided to build my own. I explored a couple of different approaches for how to do this. One was Latex, and here's one example of a latex-based planner, but I decided against as I spend too much time wrestling with it for my PhD work already. Another approach might have been Pandoc, but as far as I could tell its PDF pipeline went via Latex, so I thought I might as well cut out the middleman. Eventually I stumbled across tools to build PDFs from HTML, via "CSS Paged Media". This appealed, because I've done plenty of HTML generation. print-css.rocks is a fantastic resource to explore the print-specific CSS features. Weasyprint is a fantastic open source tool to convert appropriately-written HTML/CSS into PDF. Finally I wanted to use a templating system to take shortcuts on writing HTML. I settled for embedded Ruby, which is something I haven't touched in over a decade. This was a relatively simple project and I found it surprisingly fun. The results are available on GitHub: https://github.com/jmtd/planner. Right now, you get exactly what I have described. But my next plan is to add support for re-generating a planner, incorporating new information: pulling diary info from iCal, and any annotations made (such as with the Remarkable tablet) on top of the last generation and preserving them on the next.

Holger Levsen: 20220429-Debian-Reunion-Hamburg-2022

Debian Reunion Hamburg 2022 from May 23 to 30 This is just a quick reminder for the Debian Reunion Hamburg 2022 happening in a bit more than 3 weeks. So far 43 people have registered and thus there's still some on site accomodation available. There's no real deadline for registration, however if you register after May 1st you might not get a t-shirt in your prefered size. Also: if you attend to give a presentation but haven't replied to the CfP, please do so. The wiki page linked above has all the details.

Russ Allbery: Review: Interesting Times

Review: Interesting Times, by Terry Pratchett
Series: Discworld #17
Publisher: Harper
Copyright: 1994
Printing: February 2014
ISBN: 0-06-227629-8
Format: Mass market
Pages: 399
Interesting Times is the seventeenth Discworld novel and certainly not the place to start. At the least, you will probably want to read The Colour of Magic and The Light Fantastic before this book, since it's a sequel to those (although Rincewind has had some intervening adventures). Lord Vetinari has received a message from the Counterweight Continent, the first in ten years, cryptically demanding the Great Wizzard be sent immediately. The Agatean Empire is one of the most powerful states on the Disc. Thankfully for everyone else, it normally suits its rulers to believe that the lands outside their walls are inhabited only by ghosts. No one is inclined to try to change their minds or otherwise draw their attention. Accordingly, the Great Wizard must be sent, a task that Vetinari efficiently delegates to the Archchancellor. There is only the small matter of determining who the Great Wizzard is, and why it was spelled with two z's. Discworld readers with a better memory than I will recall Rincewind's hat. Why the Counterweight Continent would demanding a wizard notorious for his near-total inability to perform magic is a puzzle for other people. Rincewind is promptly located by a magical computer, and nearly as promptly transported across the Disc, swapping him for an unnecessarily exciting object of roughly equivalent mass and hurling him into an unexpected rescue of Cohen the Barbarian. Rincewind predictably reacts by running away, although not fast or far enough to keep him from being entangled in a glorious popular uprising. Or, well, something that has aspirations of being glorious, and popular, and an uprising. I hate to say this, because Pratchett is an ethically thoughtful writer to whom I am willing to give the benefit of many doubts, but this book was kind of racist. The Agatean Empire is modeled after China, and the Rincewind books tend to be the broadest and most obvious parodies, so that was already a recipe for some trouble. Some of the social parody is not too objectionable, albeit not my thing. I find ethnic stereotypes and making fun of funny-sounding names in other languages (like a city named Hunghung) to be in poor taste, but Pratchett makes fun of everyone's names and cultures rather equally. (Also, I admit that some of the water buffalo jokes, despite the stereotypes, were pretty good.) If it had stopped there, it would have prompted some eye-rolling but not much comment. Unfortunately, a significant portion of the plot depends on the idea that the population of the Agatean Empire has been so brainwashed into obedience that they have a hard time even imagining resistance, and even their revolutionaries are so polite that the best they can manage for slogans are things like "Timely Demise to All Enemies!" What they need are a bunch of outsiders, such as Rincewind or Cohen and his gang. More details would be spoilers, but there are several deliberate uses of Ankh-Morpork as a revolutionary inspiration and a great deal of narrative hand-wringing over how awful it is to so completely convince people they are slaves that you don't need chains. There is a depressingly tedious tendency of western writers, even otherwise thoughtful and well-meaning ones like Pratchett, to adopt a simplistic ranking of political systems on a crude measure of freedom. That analysis immediately encounters the problem that lots of people who live within systems that rate poorly on this one-dimensional scale seem inadequately upset about circumstances that are "obviously" horrific oppression. This should raise questions about the validity of the assumptions, but those assumptions are so unquestionable that the writer instead decides the people who are insufficiently upset about their lack of freedom must be defective. The more racist writers attribute that defectiveness to racial characteristics. The less racist writers, like Pratchett, attribute that defectiveness to brainwashing and systemic evil, which is not quite as bad as overt racism but still rests on a foundation of smug cultural superiority. Krister Stendahl, a bishop of the Church of Sweden, coined three famous rules for understanding other religions:
  1. When you are trying to understand another religion, you should ask the adherents of that religion and not its enemies.
  2. Don't compare your best to their worst.
  3. Leave room for "holy envy."
This is excellent advice that should also be applied to politics. Most systems exist for some reason. The differences from your preferred system are easy to see, particularly those that strike you as horrible. But often there are countervailing advantages that are less obvious, and those are more psychologically difficult to understand and objectively analyze. You might find they have something that you wish your system had, which causes discomfort if you're convinced you have the best political system in the world, or are making yourself feel better about the abuses of your local politics by assuring yourself that at least you're better than those people. I was particularly irritated to see this sort of simplistic stereotyping in Discworld given that Ankh-Morpork, the setting of most of the Discworld novels, is an authoritarian dictatorship. Vetinari quite capably maintains his hold on power, and yet this is not taken as a sign that the city's inhabitants have been brainwashed into considering themselves slaves. Instead, he's shown as adept at maintaining the stability of a precarious system with a lot of competing forces and a high potential for destructive chaos. Vetinari is an awful person, but he may be better than anyone who would replace him. Hmm. This sort of complexity is permitted in the "local" city, but as soon as we end up in an analog of China, the rulers are evil, the system lacks any justification, and the peasants only don't revolt because they've been trained to believe they can't. Gah. I was muttering about this all the way through Interesting Times, which is a shame because, outside of the ham-handed political plot, it has some great Pratchett moments. Rincewind's approach to any and all danger is a running (sorry) gag that keeps working, and Cohen and his gang of absurdly competent decrepit barbarians are both funnier here than they have been in any previous book and the rare highly-positive portrayal of old people in fantasy adventures who are not wizards or crones. Pretty Butterfly is a great character who deserved to be in a better plot. And I loved the trouble that Rincewind had with the Agatean tonal language, which is an excuse for Pratchett to write dialog full of frustrated non-sequiturs when Rincewind mispronounces a word. I do have to grumble about the Luggage, though. From a world-building perspective its subplot makes sense, but the Luggage was always the best character in the Rincewind stories, and the way it lost all of its specialness here was oddly sad and depressing. Pratchett also failed to convince me of the drastic retcon of The Colour of Magic and The Light Fantastic that he does here (and which I can't talk about in detail due to spoilers), in part because it's entangled in the orientalism of the plot. I'm not sure Pratchett could write a bad book, and I still enjoyed reading Interesting Times, but I don't think he gave the politics his normal care, attention, and thoughtful humanism. I hope later books in this part of the Disc add more nuance, and are less confident and judgmental. I can't really recommend this one, even though it has some merits. Also, just for the record, "may you live in interesting times" is not a Chinese curse. It's an English saying that likely was attributed to China to make it sound exotic, which is the sort of landmine that good-natured parody of other people's cultures needs to be wary of. Followed in publication order by Maskerade, and in Rincewind's personal timeline by The Last Continent. Rating: 6 out of 10

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