X.org randomly picks 800x600 on a monitor capable of doing 1024x768

[John Doe]

Binary package hint: xserver-xorg

When booting Ubuntu 7.04 "Feisty Fawn" Beta's "Desktop" CD, X.org 7.2.0 randomly picks the screen resolution 800x600 even though my monitor is full capable of doing 1024x768 in X.org. Just by restarting and booting my live CD again, X.org sometimes picks 1024x768 and sometimes picks 800x600. It seems like it randomly picks one resolution or another whenever I boot Ubuntu 7.04's Desktop CD. Older Ubuntu's such as 6.06 always chose 1024x768 on every boot of their Desktop CD and never swapped back and forth between 800x600 and 1024x768 depending on when I boot.

Steps for me to see the behavior:

1. Turn monitor on before computer. (I believe the monitor is a KDS XF-70).

2. Turn computer on and boot Ubuntu 7.04's Desktop CD.

Once it is booted, sometimes it picks 800x600 and sometimes it picks 1024x768. It never seems to consistently pick the same resolution on different boots.

3. If I reboot, I sometimes get 800x600 again and sometimes get 1024x768 when X.org loads.

ProblemType: Bug
Architecture: i386
Date: Sun Mar 25 12:21:12 2007
DistroRelease: Ubuntu 7.04
Uname: Linux ubuntu 2.6.20-12-generic #2 SMP Wed Mar 21 20:55:46 UTC 2007 i686 GNU/Linux

[John Doe (johndoedoejohn)]

"/var/log/Xorg.0.log" when it randomly picked 800x600 on boot of the Ubuntu 7.04 Beta Desktop CD.

[John Doe (johndoedoejohn)]

"/etc/X11/xorg.conf" when it randomly picked 800x600 on boot of the Ubuntu 7.04 Beta Desktop CD.

[John Doe (johndoedoejohn)]

"lspci -n" output when it picked 800x600

[John Doe (johndoedoejohn)]

output of:
sudo discover --disable=parallel,serial,usb,ide,scsi,pcmcia --format="%M\t%S\t%D\t%i\n" video

[John Doe (johndoedoejohn)]

Output of "sudo xresprobe nv" when it picked 800x600.

[John Doe (johndoedoejohn)]

"/var/log/Xorg.0.log" when X.org picked 1024x768.

[John Doe (johndoedoejohn)]

"/etc/X11/xorg.conf" when X.org picked 1024x768

[John Doe (johndoedoejohn)]

"lspci -n" output when X.org picked 1024x768

[John Doe (johndoedoejohn)]

output of:
sudo discover --disable=parallel,serial,usb,ide,scsi,pcmcia --format="%M\t%S\t%D\t%i\n" video

when X.org picked 1024x768

[John Doe (johndoedoejohn)]

Output of "sudo xresprobe nv" when X.org picked 1024x768.

[Timo Aaltonen (tjaalton)]

Thanks for attaching enough information before anyone could ask for it :)

It seems that the driver doesn't always get the DDC information from the monitor.

[John Doe (johndoedoejohn)]

I downloaded the Ubuntu 7.04 Daily DVD 20070407 and booted to the Live desktop on it about 4 to 5 times in a row and X.org picked 1024x768 every single time. So, I guess this issue is fixed?

[Bryce Harrington (bryce)]

Thanks for the bug report!

While the symptoms are a little different, this appears to be a dupe of 3731. The root issue is that Ubuntu failed to detect the hsync and vrefresh freqs for your monitor, and since they weren't listed in the xorg conf file, Xorg made some incorrect assumptions about them. With this incomplete information, Xorg sometimes decides to use 1024x768, and other times 800x600.

Notice in your xorg.conf file that the h/v rates aren't listed. A workaround would be to use the rates shown in your xresprobe tests (or look them up in your monitor's documentation) and add them to the monitor section of your xorg.conf file.

A true solution would be to fix whatever misdetected your monitor in the first place; since that's the goal for bug 3731, I'm marking this a dupe of that one. Please let me know if you have more info or think I'm on the wrong track here. :-)