Re: Third Monitor Stopped Working

[Dan Ritter <dsr@randomstring.org>]

On Tue, Nov 08, 2016 at 11:00:20AM +0000, Barak A. Pearlmutter wrote:
> I have three monitors, two 4K and one 1920x1200, all lined up
> horizontally: [4k][4k][1920x1200].  This configuration worked fine
> until I upgraded to stretch (testing) a few weeks ago.  Now only the two
> 4k monitors are usable, the third is off (by default) or if I force it
> on using xrandr it just mirrors.
> 
> When I run xrandr it reports a maximum horizontal resolution of
> 
>   $ xrandr | head -1
>   Screen 0: minimum 320 x 200, current 7680 x 2160, maximum 8192 x 8192
> 
> 8192.  But I need at least
> 
>   $ xrandr | egrep ' connected' | sed 's:^.* \([0-9][0-9]*\)x.*$:\1:' | awk '{t += $1} END {print t}'
>   9600
> 
> 9600.

The X server may need a little more explicit configuration: 

        SubSection "Display"
                Virtual 9600 2400
        EndSubSection

-dsr-