Tuesday, April 1, 2014

Neat drm/i915 stuff for 3.15

So the release of the 3.14 linux kernel already happended and I'm a bit late for our regular look at what cool stuff will land in the 3.15 merge window for the Intel graphics driver.

Tuesday, February 4, 2014

New drm/i915 Git Repository

So earlier this year I've signed up Jani Nikula officially as co-maintainer. Now we've also gotten around to move the drm/i915 git repository to a common location so that there's no longer a need to move it around when I'm on vacation. So everone please update any git references and remotes:

FOSDEM: Testing Kernel GPU Drivers

So as usual FOSDEM was a blast and as usual the hallway track was great too. The beer certainly helped with that ... Big props to the entire conference crew for organizing a stellar event and specifically to Luc and the other graphics devroom people.

I've also uploaded the slides for my Kernel GPU Driver Testing talk. My OCD made me remove that additional dot and resurrect the missing 'e' in one of the slides even. FOSDEM also had live-streaming and rendering videos should eventually show up, I'll add the link as soon as it's there.

Update: FOSDEM staff published the video of the talk!

Wednesday, January 15, 2014

Neat drm/i915 stuff for 3.14

Kernel v3.13 is nearing its release, so it's time at our regular look at what the next version will bring to the Intel gfx driver.

Friday, November 22, 2013

Botching up ioctls

One clear insight kernel graphics hackers gained in the past few years is that trying to come up with a unified interface to manage the execution units and memory on completely different GPUs is a futile effort. So nowadays every driver has its own set of ioctls to allocate memory and submit work to the GPU. Which is nice, since there's no more insanity in the form of fake-generic, but actually only used once interfaces. But the clear downside is that there's much more potential to screw things up.

To avoid repeating all the same mistakes again I've written up some of the lessons learned while botching the job for the drm/i915 driver. Most of these only cover technicalities and not the big-picture issues like what the command submission ioctl exactly should look like. Learning these lessons is probably something every GPU driver has to do on its own.

Tuesday, November 12, 2013

Testing Requirements for drm/i915 Features and Patches

I want to make automated test coverage an integral part of our feature and bugfix development process. For features this means that starting with the design phase testability needs to be considered an integral part of any feature. This needs to go through the entire development process, from planning, development, patch submission and final validation. For bugfixes that means the fix is only complete once the automated testcase for it is also done, if we need a new one

This specifically excludes testing with humans somewhere in the loop. We are extremely limited in our validation resources, every time we put something new onto the "manual testing" plate something else will fall off.

I've let this float for quite a while both internally in Intel and on the public mailing lists. Thanks to everyone who provided valuable input. Essentially this just codifies the already existing expectations from me as the maintainer, but those requirements haven't really been clear and a lot of emotional discussions ensued. With this we should now have solid guidelines and can go back to coding instead of blowing through so much time and energy on waging flamewars.

Saturday, November 2, 2013

Neat drm/i915 stuff for 3.13

It's that time again when the old kernel v3.12 will be released shortly and we'll take a look at what's in store for the Intel GFX driver in 3.13.

Saturday, September 21, 2013

More drm/i915 Testsuite Infrastructure

So after the recent overview over our kernel test infrastructure I've had to write a bunch multithreaded testcases. And since I'm rather lazily I've opted to create a few more helpers that hide all the little details when forking and joining processes. While at I think it's also a good time to explain a bit the infrastructure we have to help running the kernel testsuite on simulated hardware and a few other generally useful things in our testsuite helper library.

Monday, September 2, 2013

Neat drm/i915 stuff for 3.12

So kernel 3.11 will be released soonish and it's time for our regular look at what the next merge window will bring in for the intel GPU driver.

Wednesday, August 28, 2013

Recent drm/i915 Testsuite Improvements

So recently I've again wreaked decent havoc in our intel-gpu-tools kernel testsuite. And then shockingly noticed that I've never done a big pompous blog post to announce what we've started about one-a-half years ago. So besides just describing the new infrastructure for writing testcases (apparently every decent hacker must reinvent a testframework at least once ...) I'll also recap a bit what's been going on in the past.