I just got the update for xserver-xorg-core 1.19.1-4 by a d-u, and noticed that bug above mentioned in the changelog:
/usr/share/doc/xserver-xorg-core/changelog.gz:
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commit 82dcb68a8782d0cce6e6ce1a375cda05c91fe8c3
Author: Keith Packard <keithp@keithp.com>
Date: Mon Jan 9 18:10:21 2017 -0800
AttendClient of grab-pervious client must queue to saved_ready_clients [v2]
A client which is attended while a grab is blocking execution of its
requests needs to be placed in the saved_ready_clients list so that it
will get scheduled once the grab terminates. Otherwise, if the client
never sends another request, there is no way for it to be placed in
the ready_clients list.
v2: Wrap comment above mark_client_saved_ready.
Remove test for OS_COMM_IGNORED which will always be true.
Bugzilla:
https://bugs.freedesktop.org/show_bug.cgi?id=99333 Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
(cherry picked from commit 785053d033e73d2deb0ded4b97eabfd881991978)
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I did not see any freese, although I removed the workaround (DRI Level = 3).
so please have a try.