Bug#668828: phantom outputs

[Jeroen Diederen <jjhdiederen@zonnet.nl>]

I also tried to force the nouveau driver to only use one video output. 
VGA-1 and TV-1 gave me blank screens whereas forcing nouveau to use 
DVI-D-1 as the only output, gave me the same result as before (half of 
the windows are not visible).

For this to work I had to disable the monitor output in the kernel 
command as well as in an xorg.conf file. As an example, to boot into my 
powerpc powered iMac G5, forcing DVI-D-1 as output, I booted with the 
following kernel command line at the second yaboot prompt:

boot: Linux video=VGA-1:d TV-1:d

and I used an xorg.conf file with the following content:

Section "Monitor"
        Identifier "TV-1"
        Option "Ignore" "True"
EndSection

Section "Monitor"
        Identifier "VGA-1"
        Option "Ignore" "True"
EndSection


References:
http://www.mintppc.org/forums/viewtopic.php?f=15&t=810&start=10
http://en.gentoo-wiki.com/wiki/Nouveau#Phantom_and_unpopulated_output_connector_issues
http://nouveau.freedesktop.org/wiki/KernelModeSetting