We're hiring!
*

Validating changes to KMS drivers with IGT

Tomeu Vizoso avatar

Tomeu Vizoso
April 21, 2016

Share this post:

New DRM drivers are being added to almost each new kernel release, and because the mode setting API is so rich and complex, bugs do slip in that translate to differences in behaviour between drivers.

There have been previous attempts at writing test suites for validating changes and preventing regressions, but they have typically happened downstream and focused on the specific needs of specific products and limited to one or at most a few of different hardware platforms.

Writing these tests from scratch would have been an enormous amount of work, and gathering previous efforts and joining them wouldn't be much worth it because they were written using different test frameworks and in different programming languages. Also, there would be great overlap on the basic tests, and little would remain of the trickier stuff.

Of the existing test suites, the one with most coverage is intel-gpu-tools, used by the Intel graphics team. Though a big part is specific to the i915 driver, what uses the generic APIs is pretty much driver-independent and can be made to work with the other drivers without much effort. Also, Broadcom's Eric Anholt has already started adding tests for IOCTLs specific to the VideoCore-IV driver.

Collabora's Micah Fedke and Daniel Stone had added a facility for selecting DRM device files other than i915's and I improved the abstraction for creating buffers so it works for drivers without GEM buffers. Next I removed a bunch of superfluous dependencies on i915-only stuff and got a useful subset of tests to run on a Radxa Rock2 board (with the Rockchip 3288 SoC). Around half of these patches have been merged already and the other half are awaiting review. Meanwhile, Collabora's Robert Foss is running the ported tests on a Raspberry Pi 2 and has started sending patches to account for its peculiarities.

The next two big chunks of work are abstracting CRC checksums of frames (on drivers other than i915 this could be done with Google's Chamelium or with a board similar to Numato Opsis), and the buffer management API from libdrm that is currently i915-only (bufmgr). Something that will have to be dealt with in the future is abstracting the submittal of specific loads on the GPU as that's currently very much driver-specific.

Additionally, I will be scheduling jobs in our LAVA instance to run these tests on the boards we have in there.

Thanks to Google for sponsoring my time, to the Intel OTC folks for their support and reviews, and to Collabora for sponsoring Robert's, Micah's and Daniel's time.

 

Original post

Related Posts

Related Posts

Comments (0)


Add a Comment






Allowed tags: <b><i><br>Add a new comment:


Search the newsroom

Latest Blog Posts

An introduction to Linux kernel initcalls

14/07/2020

Initcalls, which serve to call functions during boot, were implemented early on in the development of the Linux Kernel. Read on as we take…

Deep dive into OpenGL over DirectX layering

09/07/2020

Earlier this year, we announced a new project with Microsoft: the implementation of OpenCL & OpenGL to DirectX translation layers. Here's…

Using syzkaller, part 4: Driver fuzzing

26/06/2020

Syzkaller is much needed tool for Linux kernel testing and debugging. With some work, it can also be enhanced to find bugs in specific drivers,…

Cross building Rust GStreamer plugins for the Raspberry Pi

23/06/2020

Previously, we discussed about how Rust can be a great language for embedded programming. In this article, we'll explain an easy setup to…

Generating MPEG-DASH streams for Open Source adaptive streaming with GStreamer

12/06/2020

Adaptive streaming is a technique to provide flexibility and scalability by offering variable bit-rate streams to the client. Here's a quick…

Bifrost meets GNOME: Onward & upward to zero graphics blobs

05/06/2020

With only free software, a Mali G31 chip can now run Wayland compositors with zero-copy graphics, including GNOME 3. We can run every scene…

Open Since 2005 logo

We use cookies on this website to ensure that you get the best experience. By continuing to use this website you are consenting to the use of these cookies. To find out more please follow this link.

Collabora Ltd © 2005-2020. All rights reserved. Privacy Notice. Sitemap.