AMDGPU Linux Driver To Finally Enable BACO For Hawaii - Allowing S4/Hibernation

The Radeon R9 290 "Hawaii" series are about seven years old almost to the day and the AMD Linux open-source driver crew is seemingly celebrating by finally adding the few lines of code needed to enable BACO power management.

Bus Active, Chip Off (BACO) is finally seeing an AMDGPU Linux kernel driver patch as we approach the end of 2020 to enable it for "Hawaii" GPUs that initially were found in the Radeon R9 290 series and later the Radeon 300 series.

This BACO support is important as it will allow these graphics cards on Linux to finally support S4 / hibernation support.

The patch posted on Tuesday amounts to just a few lines of code for wiring up Hawaii to the AMDGPU driver's BACO support. It's just a few lines of code now but it's only been more recently that AMDGPU began squaring away its BACO support. Thus back in the early days of Hawaii it wasn't as trivial to provide this support albeit for end-users still a pity it took so long for allowing these GPUs to support S4/hibernation.

Hawaii also uses the Radeon driver by default but the patch now is seemingly part of the effort in trying to get the GCN 1.0/1.1 era support on AMDGPU squared away so that it can possibly become the default driver. Still though remaining is the lack of VGA output support with AMDGPU DC as seemingly the last blocker after the other DC bits and other lingering work has been squared away. AMDGPU is most important if wanting Vulkan driver support for these older GPUs but also the possibility of some small performance improvements and just being on a more maintained driver.

In any case hopefully this AMDGPU Hawaii BACO support will make it into Linux 5.11.