Try to underclock Radeon GPU, but pp_od_clk_voltage is MISSING?

General system Gaming, sound and video
1

Below is the OP, which turns out to have been accidentally directed at my integrated GPU. Right now I’m at a dead-end because pp_od_clk_voltage is missing from /sys/class/drm/card1/device/

I have an RX 7600 that needs to be slightly underclocked. It's a hardware thing. Here's my understanding of what to do (and a summary of what I've done):

1: Append **amdgpu.ppfeaturemask=0xffffffff** to `/efi/loader/entries/<kernel>.conf`
2: Restart
3: Following [this manual](https://docs.kernel.org/gpu/amdgpu/thermal.html#pp-od-clk-voltage), command the amdgpu interface in `/sys/class/drm/card0/device/`, using commands like **echo {value} > {target}** as root.
3a: Send **manual** to `power_dpm_force_performance_level`
3b: Send a clock speed to `pp_od_clk_voltage`, like **{s / m} {1 / 0 } {Mhz}**, where "s" indicates clock speed while "m" indicates memory speed, and "1" indicates maximum clock while "0" indicates minimum. So, underclocking to 2Ghz would be **s 1 2000**.
3c: Send **c** to `pp_od_clk_voltage` to confirm the changes.

Settings can always be checked by reading `pp_od_clk_voltage`. When I start, it looks like this:
> OD_SCLK:
0:        400Mhz
1:       2200Mhz
OD_RANGE:
SCLK:     400Mhz       2200Mhz

I'll note, though, that the KDE system monitor shows the working speed of the GPU as 2400Mhz. After I follow the above instructions, `pp_od_clk_voltage` reads as:
>OD_SCLK:
0:       400Mhz
1:       2000Mhz
OD_RANGE:
SCLK:     400Mhz       2200Mhz

So, it appears to have worked. But nothing changes. I've tested it, and nothing about the system seems effected by this action. What have I missed?

I'm basically locked out of gaming if I can't get this to work; any help is appreciated.
2

I’m no HW expert, simply found this article: https://wiki.archlinux.org/title/AMDGPU#Overclocking

I assume you have seen it already, but if you haven’t, I hope it helps.
The Arch wiki is a great source of information.

3

I did look around the Arch Wiki, but somehow missed that section. Thank you. It seems I may have been operating on my integrated GPU, not my RX 7600. I think the integrated graphics are card0, and the discrete graphics are card1. But here’s a mystery: /sys/class/drm/card1/device/ DOES NOT CONTAIN pp_od_clk_voltage

?!?!

Clearly I’m not understanding something.

4

Update:

I think it’s this: https://gitlab.freedesktop.org/drm/amd/-/issues/2840
It seems that it was intentionally removed for a while, and the LTS kernel is still in that window? I’ll report back.

5

@AidanofVT
Maybe this is helpful?

6

It did end up being the kernel version. I switched to the Zen kernel and the pp_od_clk_voltage interface is right where it’s supposed to be, working as intended.

When LTI is updated to 6.7, this issue will be fixed for the few people it still effects.