gdm and gnome background don't show

[Sam Liddicott]

Binary package hint: xserver-xorg-video-displaylink

the gdm diaglog parts quickly slide to the top pixel line of the screen. I can login "blindly" and nautilus shows desktop files, but no wallpaper (just black) and no menu bars.

Right-click on desktop shows no menu but does change the appearance of the first pixel line of the screen.

It worked fine using Ubuntu 10.10 and git udlfb kernel drivers.
Ubuntu 11.04 has this bug with git udlfb drivers or with shipped drivers

[Sam Liddicott (sam-liddicott)]

Notes from this page have a fix:
http://plugable.com/2009/11/16/setting-up-usb-multiseat-with-displaylink-on-linux-gdm-up-to-2-20/

7. xrandr workaround

[update: this workaround is not needed when running xf86-video-fbdev or with recent displaylink X servers with this patch
http://git.plugable.com/gitphp/index.php?p=xf-video-udlfb&a=commit&h=54d15f63548a44c69fc3fe80191147b42061a67a
]

The DisplayLink X server currently has limited RANDR support, but later versions of GDM assume better. So for the time being, a workaround is required to get GDM applications (including gdmlogin) to display properly within the actual screen area -- otherwise they tend to think the screen has a strange rotation, and display themselves completely off it.

Add these lines into /etc/gdm/Init/Default, right after the definition of gdmwhich()

XRANDR=`gdmwhich xrandr`
if [ "x$XRANDR" != "x" ]; then
  $XRANDR -o 0
fi

I applied the fix to /etc/gdm/Init/Default and things are now working for me just as with 10.10

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.