RX 5700 XT Navi - amdgpu.ppfeaturemask=0xffffffff causes stuttering and does not unlock clock/voltage/power controls

Submitted by Xul Demonslayer @aufkrawall

Assigned to Default DRI bug account

Link to original bug (#111762)

Description

Hello,
with Polaris and Vega, setting amdgpu.ppfeaturemask=0xffffffff worked without issues here: It unlocked pp_od_clk_voltage and didn't cause any issues for me.

But with Navi, it doesn't work. I'm still not allowed to open
/sys/class/drm/card0/device/pp_od_clk_voltage
as root with specifying that flag.

Also, I can't increase the GPU's power consumption, as
/sys/class/drm/card0/device/hwmon/hwmon0/power1_cap_max
only allows the default 100% Powertune limit, meaning I can't set any higher value in
/sys/class/drm/card0/device/hwmon/hwmon0/power1_cap

Apart from not being able to change the aforementioned parameters, setting amdgpu.ppfeaturemask=0xffffffff causes stuttering, even on the desktop and also affects the mouse cursor.

This is with kernel drm-next-5.5-wip 73cdff347343504287feae8b36fa7317f04dcc61
and an MSI 5700 XT Gaming X.