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

[Maarten Lankhorst]

Op 21-06-13 12:43, Alexander E. Patrakov schreef:
> 2013/6/21 Maarten Lankhorst <maarten.lankhorst at canonical.com>:
>> 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
> According to https://help.ubuntu.com/community/HybridGraphics:
>
> echo DIS > /sys/kernel/debug/vgaswitcheroo/switch
> Connects discrete graphics with outputs.
>
> I assume this is for laptops that can dynamically switch their HDMI or
> other outputs from one card to another. However, this is completely
> different from what my Sony laptop provides. The cards and their
> outputs are physically separate. The Intel card is in the laptop, and
> can drive the internal panel, the VGA and the HDMI output. The Radeon
> card is in the dock station, is always on (there is no ATPX method in
> ACPI tables), works only from AC and has its own VGA and HDMI outputs,
> also located on the dock station. So this laptop, when docked, can
> drive five different displays, including the internal one. And I want
> to connect the TV to the HDMI output in the dock station because it is
> convenient (less cables attached to the side of the laptop itself).
>
> As I am physically away from this laptop, I cannot check whether
> vgaswitcheroo works (but assume it shouldn't).
Correct, but it should work on muxless too, switching will power off the intel, which is
why you have the second line.. It will re-enable the intel, but keep radeon as primary,
similar to what you are doing with -gpu 1.

~Maarten