https://bugs.freedesktop.org/show_bug.cgi?id=93826
--- Comment #68 from iuno@posteo.net --- (In reply to Alex Deucher from comment #67)
Do you get flickering at 144Hz without forcing the mclk to high? I.e., without these patches: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ ?id=0a646f331db0eb9efc8d3a95a44872036d441d58 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ ?id=58d7e3e427db1bd68f33025519a9468140280a75 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ ?id=09be4a5219610a6fae3215d4f51f948d6f5d2609 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ ?id=2275a3a2fe9914ba6d76c8ea490da3c08342bd19
Yes, I've experienced that before and just tested it again.
Do you know how this works on Windows? Do they increase voltage without raising clocks and could this be an option for amdgpu too?
It's not the mclk frequency or voltage, it's the blanking period for the display timing, it's apparently too short on some monitors at very high refresh rates for the mclk to finish switching in time. If part of the mclk switch happens outside of the vblank period, you end up with flickering or other display artifacts.
I assumed it is related to any voltage because higher sclk helps too. I'll just call sclk/mclk dpm states "sdpm" and "mdpm"
auto (sdpm 0, mdpm 0 or switching through states): very bad flickering and artifacts sdpm 1-7, mdpm 0: better (still flickering/artifacts, but only when bigger areas on the screen are updated) sdpm any, mdpm 1: no flickering and artifacts