Laptop + Dell monitor: no VGA output with Xrandr

mike11 · 05-16-2010, 06:48 AM

Hi All,

After connecting a Toshiba Portege to an external Dell 19" monitor xrandr -q gives:

Code:

Screen 0: minimum 320 x 200, current 1280 x 800, maximum 2048 x 2048
VGA connected 1024x768+0+0 (normal left inverted right x axis y axis) 408mm x 255mm
   1440x900       59.9 +   75.0     59.9  
   1280x1024      75.0     60.0  
   1280x800       59.8  
   1152x864       75.0  
   1024x768       75.0*    70.1     60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3     56.2  
   640x480        75.0     72.8     66.7     59.9  
   720x400        70.1  
LVDS connected 1280x800+0+0 (normal left inverted right x axis y axis) 261mm x 163mm
   1280x800       60.0*+
   1024x768       75.0     70.1     60.0  
   832x624        74.6  
   800x600        85.1     72.2     75.0     60.3     56.2  
   640x480        85.0     72.8     75.0     59.9  
   720x400        85.0  
   640x400        85.1  
   640x350        85.1  
TV disconnected (normal left inver
ted right x axis y axis)

so the VGA is recognized.
Entering

Code:

xrandr --output LVDS --mode 1280x800 --output VGA --mode 1024x768

does not activate the montiotr-it stays blank and actually reports no signal is detected.

Any ideas how to enable it?.

System:
Toshiba Portege 3000 laptop
intel Mobile 945GM/GMS, 943/940GML graphics chipset
Dell E1910 19" monitor
OS: Debian Squeeze (testing), GNOME

Thanks,
Mike.

mike11 · 05-16-2010, 07:25 AM

Update: when booting the laptop with the external monitor connected the external works (output is cloned) but the laptop screen is now clipped. It seems X11/gnome/whatever is forcing the same resolution on both displays (1440x900 is supported by the external but not by the laptop).

Will welcome any suggestions how to solve this. Cheers.

MTK358 · 05-16-2010, 07:31 AM

According to your post, it appears you use GNOME.

Possibly GNOME has its own resolution settings that interfere?

Why not use GNOME's monitor settings to set the layout and resolution?

mike11 · 05-16-2010, 07:58 PM

Thanks for replying MTK.

I assume you're referring to system->preferences->display?
It doesn't seem to affect the monitors at all. With xrandr there is momentary jitter in the screen (indicating something is being done) but with the former nothing.

Cheers.