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On my Lenovo w520, xorg/xrandr (with intel driver) detects the native resolution of my LCD panel, but doesn't seem to detect any 16:9 intermediate resolutions:

Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192           
LVDS1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 193mm                                                                          
   1920x1080      60.0*+   50.0
   1400x1050      60.0
   1280x1024      60.0
   1280x960       60.0
   1024x768       60.0
   800x600        60.3     56.2
   640x480        59.9
VGA1 disconnected (normal left inverted right x axis y axis)

The LCD panel is capable of displaying the following resolutions:

1920x1080
1600x900
1440x900
1400x1050
1366x768
1360x768
1280x1024
1280x960
1280x800
1280x768
1280x720
1024x768
960x540
800x600
640x480

So I ran X -configure and added those modes to /etc/X11/xorg.conf. After restarting Xorg, xrandr doesn't list the resolutions I added to xorg.conf. What could be the problem?

Here is my xorg.conf: http://pastebin.ubuntu.com/658761/ and my Xorg.0.log: http://pastebin.ubuntu.com/658764/

Thanks in advance

EDIT: For those who have a Lenovo ThinkPad W520 or T520 with a full HD screen, here's the xorg.conf with all supported resolutions listed: http://pastebin.ubuntu.com/659644/

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1 Answer 1

up vote 2 down vote accepted

It isn't enough to list the resolutions in the Screen section of xorg.conf. If the monitor doesn't advertise that mode, then it will ignore the mode.

Looking at the log file, you can see the mode that the video driver has queried the display for the list of modes that it supports, which match up with the output of xrandr (ignoring the doublescan modes that the driver doesn't support).

Assuming the panel actually can support the extra modes you've listed, you will need to add ModeLine directives to the Monitor section describing them, and possibly add the following to the Device section:

Option "Monitor-LVDS1" "Monitor0"

So that it knows that the monitor section refers to the LVDS output.

Determining what the required timings are will be the difficult part. If you know that these modes exist because you used them under Windows, you might be able to use the instructions from the Obtaining modelines from Windows program PowerStrip section on this wiki page:

http://www.x.org/wiki/FAQVideoModes

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Thanks for the information. Can I use modelines generated by cvt? My computer came with no OS installed, so I only have Ubuntu to use. –  Xiao-Long Chen Aug 5 '11 at 5:12
    
You could certainly give it a go. Just keep in mind that if you've never observed the system running in these other modes, some may not actually work correctly. –  James Henstridge Aug 5 '11 at 5:59
    
I ended up installing Windows on an external hard drive. Powerstrip gave an error message about not being able to read the timings from the display, so I used cvt to generate the modelines. All the modes show up in xrandr, but the refresh rates are either 59.9 or 59.6. Will that hurt the display? All the resolutions should be supported according to the technical specifications manual of the display. –  Xiao-Long Chen Aug 5 '11 at 15:11
    
Refresh rates of around 60Hz should be fine. But again, don't be surprised if you have trouble configuring some of those modes. –  James Henstridge Aug 6 '11 at 0:27
    
Two words: Thank You! I just tested all the modes--everything works fine :D –  Xiao-Long Chen Aug 6 '11 at 1:03

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