ImprovingTheLinuxKPICompatibilityLayerForTheFreeBSDGraphicsStack [FreeBSD WIKI]

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====== Engineer a Feature Complete Port of Intel's igt-gpu-tools for FreeBSD ======

  * Student: [[/JakeFreeland|JakeFreeland]]
  * Mentors: [[/EmmanuelVadot|EmmanuelVadot]] and [[/JosephMingrone|JosephMingrone]]

===== Project description =====

Intel’s igt-gpu-tools serves as a generic testing suite for drm drivers on Linux. The igt-gpu-tools suite is seperated into tests and tools where tests are the primary focus of the project. These tests target the kernel API: specifically kms, memory management, and command submission. This low-level reporting allows for transparent tracking of kernel changes and efficient debugging.

Development of igt-gpu-tools shifted in 2019 to focus on generic kms-driven tests. The vendor-agnostic foundation of kms allows for igt-gpu-tools to function on a wide range of hardware. This versatility makes igt-gpu-tools extremely helpful when developing and debugging new drm drivers. Porting the project to %%FreeBSD%% could introduce greater stability in future releases of %%FreeBSD%%’s %%LinuxKPI%%-driven drm drivers.

===== Approach to solving the problem =====

Before porting igt-gpu-tools, the CONFIG_DEBUG_FS flag must be properly implemented
in drm-kmod. The debugfs filesystem permits file sharing between the kernel and user space
for debugging purposes.Emmanuel Vadot put some debugfs patches together, but has not
upstreamed them to src yet. I will analyze the existing patches, ensure proper functionality, and
implement a clean solution before proceeding with the igt-gpu-tools port.

Once the CONFIG_DEBUG_FS implementation is complete, I will take a look at Emmanuel
Vadot and Mark Johnston’s incomplete igt-gpu-tools ports and carry over any functional code
to my new port. After all existing code has been merged, I will start my own porting process.
A high quality port will require extensive testing and debugging which will likely occupy the
remainder of this Google Summer of Code project.

===== Deliverables =====

A feature complete port of Intel's igt-gpu-tools for %%FreeBSD%%.

===== Milestones =====

June 13: Get igt-gpu-tools to compile on %%FreeBSD%% (Project Start)

June 22: Start debugfs, libprocps, libkmod implementations

June 29: Finish debugfs implementation with others on the way

July 29: Produce working KMS tests (Phase 1 Evaluation)

August 29: Produce working non-KMS tests

September 06: Ensure port is feature complete and functional (Final Submission)

November 21: Extended development and testing (Extended Final Submission)

===== Test Plan =====

With this lineup, I should be able to get a good idea of the port’s stability using the igt-gpu-tools tests and tools:
  * Sandy Bridge (2011) Intel Integrated HD Graphics
  * Radeon RDNA 2 (2020) Graphics
  * Alder Lake (2021) Intel Integrated UHD Graphics
I will walk through the igt-gpu-tools tests for each graphics processor listed above and compare results to the native Linux build. If results are significantly different, I will revisit my implementation.

===== The Code =====

[[https://github.com/jakesfreeland/igt-gpu-tools-freebsd|igt-gpu-tools Git]]
[[https://github.com/jakesfreeland/debugfs-freebsd|debugfs Git]]

===== Useful links =====

[[https://cdaemon.com/tags/gsoc2022|cdaemon: development process]]