gdm 2.30.5-0ubuntu4 regression - wrong resolution

[Jake LeMaster]

Binary package hint: gdm

Since upgrading gdm to 2.30.5-0ubuntu4 from the previous version, it fails to set the correct resolution at bootup. This is the first time it's ever done this. In the past it has always chosen my monitor's correct native widescreen resolution of 1440x900, but it's now choosing 1280x1024.

I'm using an ATI card with the default non-proprietary Xorg drivers.

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: gdm 2.30.5-0ubuntu4
ProcVersionSignature: Ubuntu 2.6.35-20.29-generic 2.6.35.4
Uname: Linux 2.6.35-20-generic i686
Architecture: i386
Date: Tue Sep 14 09:26:28 2010
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gdm

[Björn Schließmann (b-schliessmann)]

Also affected by this bug; gdm uses 1360x768 instead of 1024x768. When logging in, resolution changes to 1024x768 though. Applying 1024x768 as system default in gnome-display-properties has no effect on gdm.

$ xrandr
Screen 0: minimum 320 x 200, current 1024 x 768, maximum 4096 x 4096
VGA-0 disconnected (normal left inverted right x axis y axis)
DVI-0 disconnected (normal left inverted right x axis y axis)
LVDS connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768 60.0*+ 60.0
   1360x768 59.8
   800x600 60.3 59.9
   848x480 59.7
   720x480 59.7
   640x480 59.9 59.4
S-video disconnected (normal left inverted right x axis y axis)

[Björn Schließmann (b-schliessmann)]

The above xrandr output is while running a gnome session; see below for the same while gdm shows its login screen.

$ sudo DISPLAY=:0 xrandr
Screen 0: minimum 320 x 200, current 1360 x 768, maximum 4096 x 4096
VGA-0 disconnected (normal left inverted right x axis y axis)
DVI-0 disconnected (normal left inverted right x axis y axis)
LVDS connected 1360x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768 60.0 + 60.0
   1360x768 59.8*
   800x600 60.3 59.9
   848x480 59.7
   720x480 59.7
   640x480 59.9 59.4
S-video disconnected (normal left inverted right x axis y axis)

[Plutocrat (plutocrat)]

Ubuntu 10.10 beta.
01:05.0 VGA compatible controller: ATI Technologies Inc RC410 [Radeon Xpress 200M]
Laptop screen not capable of 1360x768, but is set as the default resolution.

[caribo (paul-caribo)]

I have the same problem on my Dell Latitude C640 with login screen set to 1360x768 instead of 1024x768.

What can/should I provide for further investigation?

[Sebastien Bacher (seb128)]

it seems similar to bug #640807