Re: [gdm-list] GDM Display problems

[Rick Wright <riwright vt edu>]

Mark Phillips wrote:

Yan,

Thanks - I tried that as well as using the "auto" button on the front to get 
the monitor to sync. Neither one worked. 

The auto button does work when the boot messages are flying by. Usually, the 
first several characters are missing, but pressing auto will fix that 
problem.

Is there an X setting I can change for the display when the gdm window is 
displayed so the monitor will sync up? Is this even possible?

Thanks again!

Mark
On Tuesday 06 September 2005 05:25 pm, Yan Seiner wrote:
  

Mark Phillips wrote:
    

If anyone has a suggestion as how to get my gdm login screen back, I would
really appreciate it.
      

Power cycle the monitor; see if it helps.  I've had a number of LCD
monitors have problems syncing; I am not sure why.  The newest one, a
nice LG, won't come out of powersave mode until you send it graphics - a
linux text screen won't do it.  I think it needs the full 1280x1024
resolution and not the 640x480 default text mode....  A bug in the
firmware, for sure.
    

Usually when the LCD (or CRT for that matter) goes black and tells you "mode not supported", then you are either driving it at too high a resolution or you do not have the horizontal & vertical sync (refresh) ranges specified correctly for the display.

This problem sounds to me like the refresh settings under the "Monitor" section of your "xorg.conf" (probably located in /etc/X11/) file are incorrect for the new LCD monitor.  My LCD takes HorizSync: 30-85 (this is kHz) and VertRefresh 50.0-90.0 (Hz) which you might try as a first go.  Really you should check the specs in the manual of your new monitor.

The other problem could be that gdm is set to use a screen resolution that is too high for this monitor.  What was the screen resolution you had set before you switched to the new LCD display?  I'm guessing that 1024x768 is as high as the new LCD can handle.  The reason you can see the text is that this is displayed at the 640x480 mode, as mentioned above.  I suspect that the desktop displays correctly (does it? - not clear from your post) because you have that set to 1024x768 (or lower).

To eliminate the possibility of faulty hardware, does everything work properly if you re-connect the original display that you just replaced?

-Rick