Linux 5.16 To Add Intel Encrypted PXP, Alder Lake S Declared Stable & Ready

A new batch of Intel kernel graphics driver code was mailed out today to DRM-Next for staging ahead of next month's Linux 5.16 kernel merge window. Lots of notable changes in this pull!

This batch of code updates for the Intel DRM kernel driver in Linux 5.16 is bringing the following changes:

- Intel's encrypted Protected Xe Path (PXP) is landing in mainline finally. Intel PXP works with Gen12 and newer as a hardware-protected session for clients on Xe Graphics with encrypted video memory and leveraging a trusted execution environment to protect these sessions from other clients. PXP on Linux has been in the works for a while but now is finally ready for mainline in Linux 5.16. The Mesa changes for PXP are pending and should be merged once the kernel bits are in mainline.

- Intel Alder Lake S (ADL-S) force_probe protection is finally removed. This means Alder Lake S graphics will be enabled by default on Linux 5.16. It's a bit surprising that the force_probe option wasn't removed already for ADL-S given the state seems/seemed to be mature on Linux 5.14~5.15, but now this is just happening for 5.16. We'll see if this and any ADL-S fixes get back-ported to prior stable series or to distribution kernels for improving the out-of-the-box experience for Alder Lake graphics given the initial chips are shipping soon. Otherwise users will need to make use of the i915.force_probe option to see Alder Lake S graphics working. With no longer hiding it behind this option, this is the point at which the Intel Linux graphics driver engineers are basically calling the support stable and ready for use.

- Adding of the DG1 PCI IDs to the kernel driver but still not binding to the initial Intel discrete graphics by default unless using the i915.force_probe module option. The DG1 code is also no longer behind the "fake local memory" compile time protection following a lot of new code this cycle further stabilizing things.

- Enabling of transparent hugepages (THP) when IOMMU is enabled to offset the performance hit caused by IOMMU usage.

- Continued bring-up of Intel Xe HP and Xe HP SDV hardware / DG2 Alchemist.

- Various code changes to try to simplify some areas of the driver and clean it up but "some performance regressions are expected."

- Continued work around moving to GuC-based submission and other GuC/HuC related work. The GuC codebase has seen a "major rework".

Or simply put, it's a very busy cycle on the Intel graphics front. The full list of patches for this initial batch of Intel GT changes targeting Linux 5.16 can be found via this pull request.