Power-saving/performance toggles for amdgpu

[Bastien Nocera]

Nearly a year later, hello again, :)

On Mon, 2020-09-14 at 01:46 -0400, Alex Deucher wrote:
> On older radeons (e.g., pre-GCN hardware), there were separate power
> states for battery and AC, but these asics are supported by the radeon
> kernel driver.  None of the hardware supported by amdgpu exposes
> anything like that anymore.  The rest is mainly for profiling and
> debugging.  For more information see the relevant kernel
> documentation:
> https://www.kernel.org/doc/html/latest/gpu/amdgpu.html#gpu-power-thermal-controls-and-monitoring
> I don't think there is anything you'd want to tweak there.

Is the power_dpm_force_performance_level sysfs property for the amdgpu
driver not something that one could tweak?
https://www.kernel.org/doc/html/latest/gpu/amdgpu.html#power-dpm-force-performance-level

System76's own power management daemon changes it:
https://github.com/pop-os/system76-power/blob/master/src/radeon.rs

So I'm wondering whether it would have any effect, for example, I would
expect setting "high" when a performance mode is requested so that
there's little latency in terms of frequency switching, "low" to force
minimal power draw in a power saving mode, and "auto" the rest of the
time.

Cheers