Intel software engineers this week sent out two pull requests landing more of their final kernel graphics driver feature changes destined for the upcoming Linux 6.14 kernel.
The feature cut-off of new material for Linux 6.14 by way of DRM-Next is quickly drawing to an end while on Tuesday were new Intel pull requests with some remaining code that was worked out and passed testing over the holidays.
First up is a new drm-xe-next pull request. Arguably most notable there is adding UHBR rates for Thunderbolt. This is the Ultra-High Bit Rate (UHBR) mode for DisplayPort with Thunderbolt in Alt-Mode. The Intel Linux kernel graphics driver was missing the UHBR modes for 10G and 20G modes. UHBR 10 allows for 40 Gbps bandwidth and UHBR 20 at 80 Gbps.
The Intel Linux driver patch adding the UHBR rates for the Thunderbolt alt-mode make mention these UHBR rates are only supported for Panther Lake “PTL” and newer platforms. So with next-gen Panther Lake systems featuring Xe3 integrated graphics you can look forward to UHBR 10 and UHBR 20 support.
The other drm-xe-next highlights from this week’s pull include:
UAPI Changes:
– OA new property: ‘unblock after N reports’i915 display Changes:
– UHBR rates for ThunderboltDriver Changes:
– IRQ related fixes and improvements
– Revert some changes that break a mesa debug tool
– Fix migration issues
– Enable GuC’s WA_DUAL_QUEUE for newer platforms
– Move shrink test out of xe_bo
– SRIOV PF: Use correct function to check LMEM provisioning
– Fix a false-positive “Missing outer runtime PM protection” warning
– Make GSCCS disabling message less alarming
– Fix DG1 power gate sequence
– Xe files fixes
– Fix a potential TP_printk UAF
– OA Fixes
– Fix tlb invalidation when wedging
– Documentation fix
Sent out yesterday was also a new drm-intel-next pull request ahead of Linux 6.14. That batch of Intel driver changes for Linux 6.14 noted “an active display round with some big series, but nothing extraordinary.” Included were:
Driver Changes:
– Some DG2 refactor to fix DG2 bugs when operating with certain CPUs
– Use hw support for min/interim ddb allocation for async flips
– More general code refactor to allow full display separation
– Expose dsc sink max slice count via debugfs
– Fix C10 pll programming sequence
– Fix DG1 power gate sequence
– Use preemption timeout on selftest cleanup
– DP DSC related fixes
– Fix HDCP compliance test
– Clean and Optimise mtl_ddi_prepare_link_retrain
– Adjust Added Wake Time with PKG_C_LATENCY
– Enabling uncompressed 128b/132b UHBR SST
– Handle hdmi connector init failures, and no HDMI/DP cases
Of that pull, the DG2/Alchemist refactoring to fix DG2 bugs with certain CPUs may be of interest to some Phoronix readers… The commit message for the Intel “Wa_14022698537” workaround explains:
“G8 power state entry is disabled due to a limitation on DG2, so we enable it from driver with Wa_14022698537. For now we enable it for all DG2 devices with the exception of a few, for which, we enable only when paired with whitelisted CPU models. This works with Native ASMP and reduces idle power consumption.”
The whitelisted CPUs are Intel CPUs of Alder Lake, Comet Lake, Kabylake, Raptor Lake, and Rocket Lake generations.
So those with some older Intel CPUs will now be able to enjoy lower CPU power consumption with DG2/Alchemist graphics cards thanks to the workaround/fixes but notable is the latest Arrow Lake generation processors not being listed here. No AMD CPUs are whitelisted either for being able to benefit from this lower DG2/Alchemist graphics card power consumption.
In any event it will be interesting to test these latest Intel Linux graphics driver changes once the Linux 6.14 kernel begins taking shape in a few weeks. The merge window should open in late January and the stable kernel out in March ahead of appearing in the likes of Fedora 42 and Ubuntu 25.04 this spring.