https://bugs.freedesktop.org/show_bug.cgi?id=106363
--- Comment #5 from Alex Deucher alexdeucher@gmail.com --- (In reply to Gregor Münch from comment #4)
(In reply to Alex Deucher from comment #3)
dpm is enabled by default on SI parts so setting dpm=1 doesn't change anything.
This depends if you use amdgpu instead of radeon on SI. In that case amdgpu.dpm seems to be disabled.
nope. dpm is enabled by default on both radeon and amdgpu.
I tried to enable DPMS and read through a bunch of tutorials configuring Xorg but nothing did work.
DPMS is not related to dpm at all.
Then I stumbled about a newsentry on phoronix mentioned this patch: https://lists.freedesktop.org/archives/amd-gfx/2018-May/022771.html There you change the behavior for CIK parts to use PP by default. The logic of this patch changes amdgpu.dpm=-1 (auto) to switch from whatever to Powerplay.
This change applies to CIK only not SI.
I started my Kernel with amdgpu.dpm=1 and everything suddenly worked like magic.
Since I dont what Powerplay actually does in the Linux world and a quick google search came up with nothing and modinfo amdgpu just reveils dpm:DPM support (1 = enable, 0 = disable, -1 = auto) (int) but nothing about Powerplay I was really under the impression that DPM also enables Powerplay. Im sorry for the confusion.
dpm and powerplay are just two sw implementations of the same hardware functionality. CIK and VI share the same SMU IP so they can share most of the power code. SI uses an old SMU block and can't share the code so it still uses the dpm implementation originally ported from radeon.