Simona Vetter's ramblings on code, bugs, graphics, hw and the utter lack of sanity in all this.
In a different epoch, before the pandemic, I’ve done a presentation about upstream first at the Siemens Linux Community Event 2018, where I’ve tried to explain the fundamentals of open source using microeconomics. Unfortunately that talk didn’t work out too well with an audience that isn’t well-versed in upstream and open source concepts, largely because it was just too much material crammed into…
EOSS in Prague was great, lots of hallway track, good talks, good food, excellent tea at meetea - first time I had proper tea in my life, quite an experience. And also my first talk since covid, pack room with standing audience, apparently one of the top ten most attended talks per LF’s conference report . The video recording is now uploaded , I’ve uploaded the fixed slides , including the missing…
The first part of this series covered principles of locking engineering . This part goes through a pile of locking patterns and designs, from most favourable and easiest to adjust and hence resulting in a long term maintainable code base, to the least favourable since hardest to ensure it works correctly and stays that way while the code evolves. For convenience even color coded, with the…
For various reasons I spent the last two years way too much looking at code with terrible locking design and trying to rectify it, instead of a lot more actual building cool things. Symptomatic that the last post here on my neglected blog is also a rant on lockdep abuse . I tried to distill all the lessons learned into some training slides, and this two part is the writeup of the same. There are…
Lockdep is giving false positives are the new the compiler is broken. — David Airlie (@DaveAirlie) August 8, 2020 Recently we’ve looked a bit at lockdep annotations in the GPU subsystems, and I figured it’s a good opportunity to explain how this all works, and what the tradeoffs are. Creating working locking hierarchies for the kernel isn’t easy, making sure the kernel’s locking validator…
Unlike the tradition of my past few talks at Linux Plumbers or Kernel conferences, this time around in Lisboa I did not start out with a rant proposing to change everything. Instead I celebrated roughly 10 years of upstream graphics progress and finally achieving paradise. But that was all just prelude to a few bait-and-switches later fulfill expectations on what’s broken this time around in…
At ELC Europe in Lyon I held a nice little presentation about the state of upstream graphics drivers, and how absolutely awesome it all is. Of course with a big focus on SoC and embedded drivers. Slides and the video recording Key takeaways for the busy: The upstream DRM graphics subsystem really scales down to tiny drivers now, with the smallest driver coming in at just around 250 lines…
lwn.net just featured an article the sustainability of open source , which seems to be a bit a topic in various places since a while . I’ve made a keynote at Siemens Linux Community Event 2018 last year which lends itself to a different take on all this: The slides for those who don’t like videos. This talk was mostly aimed at managers of engineering teams and projects with fairly little…
Aside from the regular board elections we also have some bylaw changes to vote on. As usual with bylaw changes, we need a supermajority of all members to agree - if you don’t vote you essentially reject it, but the board has no way of knowing. Please see the detailed changes of the bylaws , make up your mind, and go voting on the shiny new members page .
The DRM (direct rendering manager, not the content protection stuff) graphics subsystem in the linux kernel does not have a generic 2D accelaration API. Despite an awful lot of of GPUs having more or less featureful blitter units. And many systems need them for a lot of use-cases, because the 3D engine is a bit too slow or too power hungry for just rendering desktops. It’s a FAQ why this doesn’t…