[Nouveau] [PATCH] [RFC] drm/nouveau: bring back hdmi audio device after switcheroo power down

[Pasi Kärkkäinen]

On Wed, Jul 24, 2013 at 05:13:42PM +1000, Dave Airlie wrote:
> After a full device powerdown via the optimus power switch, we seem
> to lose the HDMI device completely on power on, this keep track of
> whether we had a hdmi audio sub function device at power on, and
> pokes a magic register to make it reappear after the optimus power
> switch is thrown.
> 
> This at least works on my NVC4 machine, probably needs testing on
> a few other laptops with other nvidia GPUs.
> 

Sorry for a stupid question, but how do you test "optimus power switch" ? 
(I have a laptop with hybrid Optimus graphics, so I could test..)

Thanks,

-- Pasi