Ubuntu
xorg-server package

  1. Bug #907381
  2. Comment #13

Comment 13 for bug 907381

Revision history for this message
Michael Fötsch (foetsch) wrote : Re: Display resolution keeps switching with external monitor connected

On 12.04 with a Radeon HD 6400M, the kernel boot option "radeon.modeset=0" seems to solve the issue (almost).

Add this to /etc/default/grub:

  GRUB_CMDLINE_LINUX="radeon.modeset=0"

Then run:

  sudo update-grub

This solves the continuous switching in the first few minutes after login. However, it still happens once a week (?) that the settings automatically go from extended desktop to mirrored at 1024x768 once or twice per session long after login. There's still a bug in there somewhere...