Implement fan_zero_rpm sysfs interface

[lichtmetzger]

@wylfen has kindly submitted a patch that makes it possible to turn off the 0rpm feature on RDNA3 cards.

I've tested it on my RX7800XT and it works. However, when doing any change in LACT, it always reverts it to the default state and I have to run:

echo '0' | sudo tee /sys/class/drm/card2/device/gpu_od/fan_ctrl/fan_zero_rpm
echo 'c' | sudo tee /sys/class/drm/card2/device/gpu_od/fan_ctrl/fan_zero_rpm

again to make it work.

I know it's not official (yet), but maybe you can add support for this in LACT? 😊

[ilya-zlobintsev]

Yeah this is promising, I've mentioned it in #255 (comment) already. I could try implementing it right now, but you'd have to test it as I do not have a system with RDNA3 and an ability to install a patched kernel currently.

[ilya-zlobintsev]

Could you post the contents of the fan_zero_rpm file?

[wylfen]

fan_zero_rpm behaves like the other files in gpu_od/, it will report the current setting and available range when read from:

FAN_ZERO_RPM:
0
OD_RANGE:
ZERO_RPM: 0 1

I'd assume that this design stays once upstreamed, but obviously can't give any guarantees. I'll poke the mailing list about an update sometime soon, too. I'm not using LACT, but wouldn't mind at all testing this.

[ilya-zlobintsev]

#393 adds support for this, if it works as intended I'll merge it once the kernel patch is accepted upstream.

[lichtmetzger]

Thank you for the quick implementation! It works well on my card.

[JosephM0on]

Hello
I have AMD RADEON RX 7800 XT, how can I do to test?

[ilya-zlobintsev]

Hello I have AMD RADEON RX 7800 XT, how can I do to test?

This currently requires compiling a patched kernel and building LACT from the pmfw-zero-rpm branch.

For general usage that doesn't require tinkering you'll need to wait until the kernel patch is accepted.

[JosephM0on]

Hello I have AMD RADEON RX 7800 XT, how can I do to test?

This currently requires compiling a patched kernel and building LACT from the pmfw-zero-rpm branch.

For general usage that doesn't require tinkering you'll need to wait until the kernel patch is accepted.

Thank you very much, I will wait without any problem, keep up the good work

[wylfen]

I don't know how long this will take to land, but the patch series has been reviewed now. We now also have another setting, fan_zero_rpm_stop_temperature.

[ilya-zlobintsev]

I don't know how long this will take to land, but the patch series has been reviewed now. We now also have another setting, fan_zero_rpm_stop_temperature.

That sounds like a useful feature as well, I'll add it once it is merged in case there will be more interface changes.

[wylfen]

FYI, both the zero RPM toggle and the stop temperature knob are now in the upstream repo.

[ilya-zlobintsev]

I've updated the PR with the new parameter name and added a fan stop temperature option. I will merge it when someone is able to confirm that it is working.

[ilya-zlobintsev]

This has been merged, and you can use it if you run a recent linux-next kernel. It will land in 6.13 if running a stable version.