[Bug 74551] Unable to run linux with radeon.runpm=1

bugzilla-daemon
2014-07-18T05:36:52Z

--- Comment #16 from maxis11 <ya.maxis11@yandex.ru> ---
(In reply to Alex Deucher from comment #15)
> (In reply to maxis11 from comment #13)
> > (In reply to Alex Deucher from comment #12)
> > > (In reply to maxis11 from comment #6)
> > > > BTW runpm works with 3.12.7 and 3.12.8 (with 3.13 and later runpm=1 freezes
> > > > laptop during boot)
> > >
> > > runpm support didn't exist until 3.13. If "echo OFF >
> > > /sys/kernel/debug/vgaswitcheroo/switch" has never worked, then your system
> > > has never had functional support for turning on/off the dGPU.
> >
> > kernel 3.12.7:
> > When loading SUMO2(6480g)
>
> That's not runpm, that's dpm (dynamic power management). Runpm turns the
> dGPU off completely when it's not in use. Dpm dynamically adjusts the
> clocks and voltages of the GPU when it's powered on. Prior to 3.13, runpm
> was not available and the dGPU was always powered on unless you manually
> powered it off via debugfs.

So it seems that this is Acer BIOS problem freezes laptop, when trying to turn
off dGPU. Am I right?