Thanks, I attached the logs you requested. With 1.11.9-0ubuntu1 the problem presists. I don't know when exactly it started but it happend relatively recently. It might be a issue with the setup of X done by lightdm, because when I launch my session via gdm I don't see this problem.
Whats interessting is that lsof shows me that fd0 is connected as 0w to /var/log/Xorg.0.log for both gdm/lightdm but the select() for lightdm includes fd 0 in the select loop but for gdm it does not include it. And lightdm has a slightly different set of options when it launches X - i.e. -mir which is not set by gdm. -- 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