Radeon 6800 XT: 100% GPU core usage & 74 Watts when idle

[piorunz <piorunz@gmx.com>]

Hello,

I am using Bullseye 11 with Radeon 6800 XT and noticed higher
temperature and noise comparing to Windows, so I investigated this and
found the fault. GPU core works at 100% usage at all times, even at idle.

$ cat /sys/class/drm/card0/device/gpu_busy_percent
99

$ sensors
(...)
amdgpu-pci-0900
Adapter: PCI adapter
vddgfx:        1.14 V
fan1:        1098 RPM  (min =    0 RPM, max = 3000 RPM)
edge:         +51.0°C  (crit = +100.0°C, hyst = -273.1°C)
                       (emerg = +105.0°C)
junction:     +55.0°C  (crit = +110.0°C, hyst = -273.1°C)
                       (emerg = +115.0°C)
mem:          +56.0°C  (crit = +100.0°C, hyst = -273.1°C)
                       (emerg = +105.0°C)
power1:       74.00 W  (cap = 272.00 W)

gpu-mon (from rickslab-gpu-utils)
┌─────────────┬────────────────────┐
│Card #       │card0               │
├─────────────┼────────────────────┤
│Model        │ Navi 21 RX         │
│GPU Load %   │99                  │
│Mem Load %   │0                   │
│VRAM Usage % │4.839               │
│GTT Usage %  │0.802               │
│Power (W)    │75.0                │
│Power Cap (W)│272.0               │
│Energy (kWh) │0.0                 │
│T (C)        │53.0                │
│VddGFX (mV)  │1143                │
│Fan Spd (%)  │0                   │
│Sclk (MHz)   │2470                │
│Sclk Pstate  │1                   │
│Mclk (MHz)   │1000                │
│Mclk Pstate  │3                   │
│Perf Mode    │0-BOOTUP_DEFAULT    │
└─────────────┴────────────────────┘


This is my hardware:
$ inxi -G
Graphics:  Device-1: Advanced Micro Devices [AMD/ATI] Navi 21 [Radeon RX
6800/6800 XT / 6900 XT] driver: amdgpu v: kernel
           Display: x11 server: X.Org 1.20.11 driver: loaded:
amdgpu,ati unloaded: fbdev,modesetting,radeon,vesa resolution:
           1: 1920x1200~60Hz 2: 3840x2160~60Hz
           OpenGL: renderer: AMD SIENNA_CICHLID (DRM 3.40.0
5.10.0-8-amd64 LLVM 11.0.1) v: 4.6 Mesa 20.3.5

All packages are default from Bullseye (apart from rickslab-gpu-utils
package which I installed to debug this issue), fresh install from the
scratch a week ago, all graphics and games works perfectly. It's just
that 100% GPU usage when idle. 74 Watts used when idle! I did further
testing and found out this:

Windows 10
one monitor: 9-11 W, GPU clock 0-10 MHz, Memory Clock 40-100 MHz
two monitors: 34 W, GPU clock 0-10 MHz, Memory Clock 2000 MHz

Debian 11
one monitor: 74 W, GPU clock 2475 MHz, Memory Clock 2000 MHz
two monitors: 74 W, GPU clock 2475 MHz, Memory Clock 2000 MHz

Debian results are very bad! On Windows 10, high memory clock with two
monitors it's a known issue, but on Debian also 100% GPU usage and
2.5GHz GPU core clock is a big problem.

Any tips appreciated.

--

With kindest regards, piorunz.

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