Upgraded today xorg-server to 188.8.131.521-r5..
And spent 2 hours trying to revive my KDE+Xorg.
Symptoms: Xorg starts, mouse cursor appears, and you can move it. Then kdm tries to start.. and everything hangs. No reaction to ctrl-alt-backspace, no reaction to ctrl-alt-del, only can reboot my laptop holding its “power” button for a few seconds.
Backtrace: 0: /usr/bin/X(xorg_backtrace+0x38) [0x8139f98]
Fatal server error:
Caught signal 11. Server aborting
Please consult the The X.Org Foundation support
Please also check the log file at “/var/log/Xorg.1.log” for additional information.
and nothing more.
I tried to rebuild xf86-input-* – nothing changed.
Helped only downgrading to xorg-server-184.108.40.2061-r4.
So, r5 is a good candidate for /etc/portage/package.mask :)