I installed unity8-destktop-session-x11 to test click on the desktop but I did not change any config (to my knowledge :) except for installing this package. I actually thought I had unity8-desktop-session-mir installed, but it seems that during testing I moved to the other one. And indeed, when I remove unity8-desktop-session-x11 the 100% CPU problem goes away.
Here is the output of lightdm --show-config with the unity8-desktop-session-x11 package installed: """ [SeatDefaults] A type=unity;xlocal A unity-compositor-command=unity-system-compositor.sleep J user-session=ubuntu C greeter-wrapper=/usr/lib/lightdm/lightdm-greeter-session E guest-wrapper=/usr/lib/lightdm/lightdm-guest-session H greeter-session=lightdm-gtk-greeter G xserver-command=X -core [LightDM] J session-wrapper=/etc/lightdm/Xsession J minimum-vt=7 J seats=seat-0 [GuestAccount] J enabled=true J username=guest J setup-script=/usr/share/lightdm/guest-session/guest-session-setup.sh J cleanup-script=/usr/share/lightdm/guest-session/guest-session-cleanup.sh Sources: A /usr/share/lightdm/lightdm.conf.d/10-unity-system-compositor.conf (null) mand.conf C /usr/share/lightdm/lightdm.conf.d/50-greeter-wrapper.conf E /usr/share/lightdm/lightdm.conf.d/50-guest-wrapper.conf E /usr/share/lightdm/lightdm.conf.d/50-guest-wrapper.conf (null) mand.conf G /usr/share/lightdm/lightdm.conf.d/50-xserver-command.conf H /usr/share/lightdm/lightdm.conf.d/60-lightdm-gtk-greeter.conf [Invalid UTF-8] (null) \xe8\x87\xa9\xc8@\x7f J /etc/lightdm/lightdm.conf """ I see the 100% CPU with different environments like "mate" too, but lightdm is using the same commandline for X, i.e. its running with -mir -mirSocket when the u-d-s-x11 package is installed. Feel free to reassign to Xmir. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1365855 Title: 100% cpu in Xorg when xorg is started via lightdm Status in “lightdm” package in Ubuntu: Incomplete Bug description: I see Xorg using 100% cpu when its running via lightdm. This is not the case if I start X via "startx" or when its run from lxdm or gdm. A strace from a VT shows constant activity (where gdm has only a select() waiting). Most notably this repeats: """ select(256, [0 1 3 5 13 24 25 26], NULL NULL {417 413000}) = 1 (in [0], left {417, 412998}) read(0, 0x7ffff2bef74a0, 1024) = -1 (Bad file descriptor) """ (transcripted from the affected machine). To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1365855/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
