idle power consumption of Polaris 20 GPU reported too high in amdgpu_pm_info

Submitted by Xul Demonslayer @aufkrawall

Assigned to Default DRI bug account

Link to original bug (#108942)

Description

Created attachment 142715
xorg log

It looks like this:

/sys/kernel/debug/dri/0/amdgpu_pm_info

Clock Gating Flags Mask: 0x3fbcf
Graphics Medium Grain Clock Gating: On
Graphics Medium Grain memory Light Sleep: On
Graphics Coarse Grain Clock Gating: On
Graphics Coarse Grain memory Light Sleep: On
Graphics Coarse Grain Tree Shader Clock Gating: Off
Graphics Coarse Grain Tree Shader Light Sleep: Off
Graphics Command Processor Light Sleep: On
Graphics Run List Controller Light Sleep: On
Graphics 3D Coarse Grain Clock Gating: Off
Graphics 3D Coarse Grain memory Light Sleep: Off
Memory Controller Light Sleep: On
Memory Controller Medium Grain Clock Gating: On
System Direct Memory Access Light Sleep: Off
System Direct Memory Access Medium Grain Clock Gating: On
Bus Interface Medium Grain Clock Gating: Off
Bus Interface Light Sleep: On
Unified Video Decoder Medium Grain Clock Gating: On
Video Compression Engine Medium Grain Clock Gating: On
Host Data Path Light Sleep: On
Host Data Path Medium Grain Clock Gating: On
Digital Right Management Medium Grain Clock Gating: Off
Digital Right Management Light Sleep: Off
Rom Medium Grain Clock Gating: On
Data Fabric Medium Grain Clock Gating: Off

GFX Clocks and Power:
300 MHz (MCLK)
300 MHz (SCLK)
600 MHz (PSTATE_SCLK)
1000 MHz (PSTATE_MCLK)
750 mV (VDDGFX)
29.159 W (average GPU)

GPU Temperature: 28 C
GPU Load: 0 %

But: Physical wattmeter measures 38W for the whole system. So apparently, the reported power usage in amdgpu_pm_info must be wrong for idle.

Power consumption of the whole system is a bit lower on Windows (30W). So probably GPU power saving doesn't work as good as on Windows, but this doesn't explain the unrealistic number reported in amdgpu_pm_info.

I btw. also noticed that power saving of Vega works much better than of Polaris on Linux. With Polaris, the clocks get up real quickly for even the slightest amount of GPU load. Vega saves much more power and doesn't stutter, despite of the higher savings.

I had a RX 560 before the RX 580, and I think its idle power consumption was correctly reported with something like 3W (not 30) or so.

latest 4.21-wip kernel

Attachment 142715, "xorg log":
Xorg.0.log