I think I was affected by this issue , which lead me to this error message after unloading Xorg :
sudo modprobe radeon [ 301.718377] [drm:radeon_init] *ERROR* No UMS support in radeon module! I had to force kms by : grep radeon /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT="radeon.modeset=1" As suggested I updated kernel : Linux version 3.16.0-29-generic (buildd@toyol) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #39-Ubuntu SMP Tue Dec 16 20:53:40 UTC 2014 So to move foreward Isnt modeset module arg supposed to be enabled by default ? how to check ? modinfo radeon | grep modeset parm: modeset:Disable/Enable modesetting (int) vermagic: 3.16.0-29-generic SMP mod_unload modversions 686 Various notes at : http://rzr.online.fr/q/radeon_7000_ve I'll may update later ... -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-ati in Ubuntu. https://bugs.launchpad.net/bugs/1318202 Title: System won't boot unless nomodeset option is selected [ubuntu 14.04] To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/1318202/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : [email protected] Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
