Intel Meteor Lake Graphics Receive Latest Enablement Patches In Linux 6.4

The final batch of work from Intel for the Meteor Lake graphics "drm-intel-gt-next" has been uploaded to the Linux 6.4 kernel, patiently awaiting the merge window that should open in a few more weeks. The window will open shortly after the new version of Linux (v. 6.3) becomes life for download.

Intel Meteor Lake Graphics receives the final pieces to drm-intel-gt-next enablement for Linux 6.4 merge window

Intel has centrally focused on the enablement of Meteor Lake integrated graphics support. Since the new Meteor Lake line will target mobile platforms first, the integrated graphics, also known as the tGPU (Tiled GPUs) will be integrated into these chips offering equal capabilities as Alchemist-based discrete graphics, or DG2 architecture.

Joonas Lahtinen, one of the Intel engineers working on the project, exclaims the group's finality of the work on drm-intel-gt-next to Daniel Airlie and Daniel Vetter.

Here goes the final drm-intel-gt-next pull request for v6.4.

As top items we have a fix for context runtime accounting, Meteorlake
enabling, DMAR error noise elimination due to GPU error capture, BAR
resizing forcewake fix and memory contents clearing fix for discrete.
More robust GuC loading on systems with IFWI that leaves GPU to slow
frequency and a potential UAF closed on perf add_config IOCTL.

There is also change to the uAPI headers to eliminate flexible-array
member kernel-wide request, which does not impact binaries and also
should not impact compilation.

— Joonas Lahtinen from the recent drm-intel-gt-next pull request

The original text from the drm-intel-gt-next has been altered slightly for readability, but the UAPI and driver changes are listed below.

drm-intel-gt-next-2023-04-06:

UAPI Changes:

• (Build-time only, should not have any impact) drm/i915/uapi: Replace fake flex-array with flexible-array member

"Zero-length arrays as fake flexible arrays are deprecated and we are moving towards adopting C99 flexible-array members instead."

This is on core kernel request moving towards GCC 13.

Driver Changes:

• Fix context runtime accounting on sysfs fdinfo for heavy workloads (Tvrtko)
• Add support for OA media units on MTL (Umesh)
• Add new workarounds for Meteorlake (Daniele, Radhakrishna, Haridhar)
• Fix sysfs to read actual frequency for MTL and Gen6 and earlier (Ashutosh)
• Synchronize i915/BIOS on C6 enabling on MTL (Vinay)
• Fix DMAR error noise due to GPU error capture (Andrej)
• Fix forcewake during BAR resize on discrete (Andrzej)
• Flush lmem contents after construction on discrete (Chris)
• Fix GuC loading timeout on systems where IFWI programs low boot frequency (John)
• Fix race condition UAF in i915_perf_add_config_ioctl (Min)
• Sanitycheck MMIO access early in driver load and during forcewake (Matt)
• Wakeref fixes for GuC RC error scenario and active VM tracking (Chris)
• Cancel HuC delayed load timer on reset (Daniele)
• Limit double GT reset to pre-MTL (Daniele)
• Use i915 instead of dev_priv insied the file_priv structure (Andi)
• Improve GuC load error reporting (John)
• Simplify VCS/BSD engine selection logic (Tvrtko)
• Perform uc late init after probe error injection (Andrzej)
• Fix format for perf_limit_reasons in debugfs (Vinay)
• Create per-gt debugfs files (Andi)
• Documentation and kerneldoc fixes (Nirmoy, Lee)

• Selftest improvements (Fei, Jonathan)

Michael Larabel, lead developer on the Phoronix Test Suite, Phoromatic, & OpenBenchmarking.org, and the founder of the Linux hardware site Phoronix states that Meteor Lake graphics are currently seen as an "experimental and behind-the-force" option. However, it is fantastic for Linux users to have Intel support ready with the recent enablement, especially with the processors shipping later this year. Larabel anticipates Meteor Lake enablement will be accessible within Linux version 6.5.

Those interested in the complete pull request submitted yesterday can check out the link here for more information.

Written by Jason R. Wilson