[ltp] xrandr output switching and debian (see bug #456778)

[Carlos Moffat]

On Tue, 2008-01-29 at 10:27 +0100, Csillag Tamas wrote:
> hi,
> 
> I am using Debian unstable on my Thinkpad X40.
> 
> I remember that I was able to switch to the external VGA output with the
> right Fn+Hotkey combination.
> 
> That functionality is gone. I was using: reboot the machine with the VGA
> connected as a workaround (it is very inconvinient). Then I discovered
> xrandr on debian wiki http://wiki.debian.org/XStrikeForce/HowToRandR12.
> Now with simple commands I can switch outputs:
> 
> autodetect and use all outputs with their defaults:
> xrandr --auto
> 
> switch off VGA output:
> xrandr --output VGA --off
> 
> switch off internal display output:
> xrandr --output LVDS --off
> 


Hi Cstamas,

I use a little script to do this, which I modified from a code I found
somewhere else. I've been too lazy to hook it to any Hotkey:

#!/bin/bash

mode=$1

if [ -z "$mode" ]
then
        echo "Usage: $0 <mode>" >&2
        exit 1
fi

if [ "$mode" == "single" ]
then
        xrandr --output LVDS --auto --mode 1600x1200 --dpi 133  --output
VGA-0 --off
        xvattr -a XV_CRTC -v 0
        gconftool-2 --set /desktop/gnome/font_rendering/dpi --type float
100
elif [ "$mode" == "dual" ]
then
        xrandr  --auto
        xrandr --output VGA-0 --auto --mode 1280x1024 --dpi 86 --output
LVDS --off
        gconftool-2 --set /desktop/gnome/font_rendering/dpi --type float
86
        xvattr -a XV_CRTC -v 1
else
        echo "Unknown mode $mode" >&2
        exit 1
fi

I use this code doing 'xmode dual' when I run a external monitor or
'xmode single' when... well, it's pretty obvious. 

I use gnome, so the code also changes the dpi value, and the xvattr
makes sure the video overlay is in the right screen (although I haven't
tried whether this is right or not). Of course, you'll need to change
the 

Whatever desktop you're using, it is useful to have a keyboard shortcut
to 'xrandr --auto'. I use 'Ctrl-Alt-s', which ensures that if something
goes wrong with the screen detection, I can always get my screen back.

Hope this helps.
Carlos




> It would be nice to use the acpi hotkeys for this. I already filed a
> bug: http://bugs.debian.org/456778 But quite frankly I do not know how
> to do it properly on distribution wide, where multiple outputs: SVIDEO
> VGA are available.
> 
> So if you have an idea on this please tell me and if we reach the
> conclusion I will forward it to the debian bts.
> 
> Thanks in advance!
> 
> Regards,
>   cstamas
> -- 
> CSILLAG Tamas (cstamas) - http://digitus.itk.ppke.hu/~cstamas
> 
> Put your hand on a hot stove for a minute, and it seems like an hour.
> Sit with a pretty girl for an hour, and it seems like a minute.
> That's relativity.                                   -- Albert Einstein
>