[Bug 70651] cannot write to power_dpm_force_performance_level: invalid argument (radeon 7730m)

bugzilla-daemon
2014-02-24T15:21:14Z

--- Comment #7 from Alex Deucher <alexdeucher@gmail.com> ---
That patch is against 3.14rc; it should apply there. The issue is that on
hybrid laptops, the dGPU is powered down when not in use so you can't make
adjustments to the dGPU when it's powered down. It doesn't make sense to power
it up to make the adjustments since it will just be powered down again right
after. As such the values you are reading back are garbage since the hw is
powered down. The patch just attempts to do something sensible when you try
and access the hw via sysfs or debugfs and the dGPU is powered down. You can
disable the automatic dGPU power down by setting radeon.runpm=0 on the kernel
command line in grub.