Display resolution sometimes wrong on power up

NoOp glgxg at sbcglobal.net
Tue Jun 30 20:27:20 UTC 2009

On 06/30/2009 12:21 AM, Colin Law wrote:
> 2009/6/28 NoOp <glgxg at sbcglobal.net>:
>> On 06/28/2009 04:14 AM, Colin Law wrote:
>>> I have a strange situation with one of my machines. Running Jaunty
>>> Desktop (new installation). Sometimes on power up the display goes to
>>> 800x600 instead of 1024x768.  If I then run xrandr it shows only
>>> 800x600 and 640x480.  If I logout and in again then it goes to
>>> 1024x768 and xrandr shows the full set of valid settings.  I have
>>> Visual Effects off.
>> Does it make a difference if the display is off/on when you boot? Try it
>> both ways (hard boot's not just restart) to test. If it only occurs when
>> the display is turned off during boot then you may have to modify add
>> the display specs to your xorg.conf file. What is the specific brand &
>> model of the display?
> Rather non-intuitively I have not managed to make it fail if the
> monitor is powered off.  It seems to fail about once in five times if
> the monitor is on.  It is possible that it does fail when monitor off
> but I have just not managed to hit it.

Interesting... it's usually the other way around.

> It is a Dell M782p monitor.  I am guessing that for some reason the
> monitor is not being correctly identified on start up.  I suppose the
> identification circuitry must be powered by from the PC otherwise it
> would never work if the monitor was off.  Is the detection logged
> somewhere?  I had a look but could not find anything, but I was likely
> looking in the wrong log.

Look in /var/log/Xorg.0.log. Make a copy of the log when it's working &
then compare against the one that is not. Or just compare Xorg.0.log
against Xorg.0.log.old.
  Note: Meld is excellent for doing this:
http://packages.ubuntu.com/jaunty/meld - 'sudo apt-get install meld' &
you'll find it in Applications|Programing|Meld Diff Viewer.

I'd also have a look at ~/.xsession-errors as well to see if anything
shows up there.

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