AMD Readies New Radeon Driver Code For Linux 5.17: STB, Seamless Boot For Van Gogh
AMD's Alex Deucher sent out the initial batch of changes for queuing in DRM-Next until the Linux 5.17 merge window. This is just the first of multiple expected pull requests over the next few weeks.
While recent Linux kernel series brought a lot of additions to AMDGPU including new hardware support and features like DisplayPort 2.0, this initial pull request at least isn't too exciting from the end-user perspective. Some of the early AMDGPU changes for Linux 5.17 include many fixes such as around Panel Self Refresh (PSR) handling for laptops, Display Stream Compression (DSC), OLED backlight handling, APU clock querying, SR-IOV, and various other fixes.
When it comes to feature work, there is Smart Trace Buffer handling for helping to isolate failures with select dGPUs and akin to the AMD Smart Trace Buffer CPU support that has also been recently worked on for the Linux kernel. AMD Smart Trace Buffer is basically a cyclic data buffer having log information about system execution for helping to analyze failures. The STB is always running and can be dumped when an error occurs without having to reproduce it or run any extra instrumentation. The Smart Trace Buffer dumping is via DebugFS and this functionality is initially in place for RDNA2 dGPUs.
Another new feature is getting seamless boot functionality working for DCN 3.01 display hardware. DCN 3.01 is found with Van Gogh APUs. AMDGPU's Seamless Boot functionality is about smoothing the start-up experience by trying to avoid redundant / unnecessary mode-sets and provide a seamless/flicker-free boot experience.
The initial set of AMDGPU (and AMDKFD) kernel driver patches on their way to DRM-Next for Linux 5.17 can be found via this pull request. Again, we'll see what more feature code AMD has ready in the next few weeks to still make it for v5.17.