[RndTbl] Monitor detection

John Lange john.lange at open-it.ca
Wed Jul 11 13:20:57 CDT 2007


Thanks Scott.

read-edid does not seem to exist on my system.

And I don't think xrandr is what I need. It seems to report your current
settings and allow you to change things.

As you can see from this output, I've got two monitors connected in
xinerama mode (thus the 2800 x 1050 resolution) but there is no
indication from the output about the second monitor.

# xrandr -q
SZ:    Pixels          Physical       Refresh
*0   2800 x 1050   ( 757mm x 303mm )  *60  
1   1400 x 1050   ( 757mm x 303mm )   60  
2   1280 x 1024   ( 757mm x 303mm )   60   47   43  
3   1152 x 864    ( 757mm x 303mm )   60   47   43  
...

What I'm trying to do is have the laptop detect when a second monitor is
connected during boot and automatically put the system into xinerama
mode. When no monitor is detected it should default to clone mode.

Currently this is strictly a manual process for me now during boot but
its a bit of a pain.

>From playing around with MythTV I know the video card has the ability to
detect what devices are connected. I just need to figure out the command
line way of getting this information.

Regards,

John

On Wed, 2007-07-11 at 13:05 -0500, Scott Balneaves wrote:
> John Lange wrote:
> > I know someone mentioned this at a distant past MUUG meeting; what is
> > the command line tool that will query the attached monitor for its
> > settings? I believe this is called DDC?
> 
> If you're looking for the low level bit, I think read-edid is what you're
> looking for.
> 
> However, if you're on a modern xorg based distro, xrandr is a good one:
> 
> oin$ xrandr -q
>   SZ:    Pixels          Physical       Refresh
> *0   1280 x 1024   ( 342mm x 271mm )  *75   60
>   1   1024 x 768    ( 342mm x 271mm )   75   70   60
>   2    832 x 624    ( 342mm x 271mm )   75
>   3    800 x 600    ( 342mm x 271mm )   75   72   60   56
>   4    640 x 480    ( 342mm x 271mm )   75   73   60
>   5   1280 x 960    ( 342mm x 271mm )   60
>   6   1280 x 800    ( 342mm x 271mm )   60
>   7   1152 x 864    ( 342mm x 271mm )   75
>   8   1280 x 768    ( 342mm x 271mm )   60
>   9   1152 x 768    ( 342mm x 271mm )   55
>   10   416 x 312    ( 342mm x 271mm )   75
>   11   400 x 300    ( 342mm x 271mm )   75   72   60
> Current rotation - normal
> Current reflection - none
> Rotations possible - normal
> Reflections possible - none
> 
> xrandr will allow you to do all sorts of cool things.  If it's an
> intel chipset, you can switch monitors, etc etc etc.
> 
> Scott
> 



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