[RFC PATCH v2] xfree86: add a -gpu switch to select primary gpu

[Maarten Lankhorst]

Op 20-06-13 19:49, Alexander E. Patrakov schreef:
> 2013/6/12 Maarten Lankhorst <maarten.lankhorst at canonical.com>:
>> Well with the detection bug fixed, here's the patch in a slightly cleaned up form,
>> tested with nvidia and nouveau. :-)
> Also tested on my Sony VAIO VPCZ23A4R laptop. For the first time, the
> AMD equivalent of Optimus worked as intended: I could assign the
> Radeon card to be the primary, and send output both to the TV
> connected to it via HDMI and to the eDP panel connected to the Intel
> card. No dirty artifacts, unlike the "reverse optimus" solution (intel
> rendering to radeon outputs) by Dave Airlie. Thanks!
>
> Wishlist: the laptop's radeon card is actually in a dock station that
> may or may not be connected on a given boot. So, I would like to use
> radeon (-gpu 1) as the primary gpu only if it exists - but there is no
> syntax to do that.
For the open source drivers there should be a different way to do so, try
running this before starting X:

if [ -f /sys/kernel/debug/vgaswitcheroo/switch]; then
  echo DIS > /sys/kernel/debug/vgaswitcheroo/switch
  echo ON > /sys/kernel/debug/vgaswitcheroo/switch
fi