I believe this may be a kernel regression. I can repro on 15.04 with sddm by installing any 4.x series kernel, haven't done any bisecting, and can't find anything interesting in dmesg (when I can switch to a vc sucessfully after X starts but fails to output anything), but with a single change from 3.19 to any of the mainline PPA 4.x kernels, the problem is immediately evident, and occasinally CPU locks up (SKL), but only when both GPUs are enabled (I have a BIOS hardware mux that I can use to force Nvidia only, which is what I'm doing currently to have a usable system and avoid recompiling iwl 8260 drivers for 3.19 every kernel update).
-- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/1501041 Title: No visible display in non gnome sessions when using nvidia drivers via nvidia-prime until screen goes to sleep, then waked up To manage notifications about this bug go to: https://bugs.launchpad.net/lightdm/+bug/1501041/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
