Radeon Vega 64 MCLK stuck at 100% speed on dual monitor setup
Brief summary of the problem:
I've purchased a new monitor for stream using Manjaro so, when I connect and configure everything seems to go well. However, once I check the GPU idle parameters, I notice that the memory frequencies are stuck at 100% speed (945MHz all the time) so I tried to change the graphical server (from wayland to Xorg) but seems that the problem persist.
Seems that only happens when the secondary monitor is connected because as soon as I connect the second one the frequencies rise again, on the other hand, If I run it with only one monitor the frequencies remain low. If I disconnect the secondary monitor after that, it still remains at 100% and I have to restart the system completely to return to normal parameters. I've tried adding kernel parameters to the GRUB boot like amdgpu.dc=0 and amdgpu.dcfeaturemask=2 with no better result. I really don't know if this is normal on linux or a it's a bug but as a first glance, using windows with same settings, the idle GPU frequencies remain low (167MHz) I use radeontop to read GPU parameters.
Hardware description:
- CPU: AMD Ryzen 2700X
- GPU: AMD RADEON VEGA 64
- System Memory: 16GB DDR4 3200
- Display(s): Primary 2560X1080 (HDMI) and secondary 1920X1080 (DP) both at 75Hz and freesync enabled
- Type of Display Connection: DP and HDMI
System information:
- Distro name and Version: Manjaro KDE minimal
- Kernel version: 5.16.14-1
- AMD official driver version: Mesa 21.3.7-2
How to reproduce the issue:
- Power on the system.
- Plug a secondary screen.