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A pull request of early AMDGPU kernel graphics driver changes was submitted for DRM-Next on Friday as some of the early feature work accumulating for the Linux 6.4 kernel cycle.
Among the AMDGPU kernel driver changes this round are a number of fixes affecting items such as the UMC RAS, DCN 3.2, FreeSync, SR-IOV, various IP blocks, USB4, and more. On the feature side, mentioned subtly in the change-log are a few power-related additions… These additions are largely focused on Van Gogh APUs, which is notably for the Valve Steam Deck and benefiting its graphics moving forward.
First up, this kernel pull request introduces a new sysfs interface for adjusting/setting thermal throttling. This is wired up for Van Gogh and allows reading/updating the thermal limit temperature in millidegrees Celsius. This “APU thermal cap” interface is just wired up for Van Gogh and seems to be Steam Deck driven feature work so that SteamOS will be better able to manage the thermal handling of the APU graphics.
Among the AMDGPU kernel driver changes this round are a number of fixes affecting items such as the UMC RAS, DCN 3.2, FreeSync, SR-IOV, various IP blocks, USB4, and more. The pull request just mentions for “supported APUs” with these power changes while digging through the code is where it points just to being handled on Van Gogh currently.
These power features will be exposed via sysfs while Steam OS will wrap around them intelligently and possibly some new UI settings knobs for those wanting more control over their Steam Deck’s thermal/performance.
There is also a fix/workaround in this pull too for disabling indirect SRAM on Van Gogh APUs with “broken” BIOSes to fix the AMD VCN handling on older Steam Decks with out-of-date BIOS versions.
Over on the AMDKFD compute driver side, this pull request has support now for exporting buffers via DMA-BUF, multi-VMA page migration fixes, and other fixes.
See this pull request for the full list of initial AMDGPU/AMDKFD patches queuing ahead of the Linux 6.4 cycle that will kick off in May while the stable release will be out this summer.