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Olivier Fourdan b79eaf1184 xwayland: handle EAGAIN on Wayland fd
wl_display_flush() can fail with EAGAIN and Xwayland would make this a
fatal error.

When this happens, it means that Xwayland has flooded the Wayland file
descriptor, either because the Wayland compositor cannot cope or more
likely because of a deadlock situation where the Wayland compositor is
blocking, waiting for an X reply while Xwayland tries to write data to
the Wayland file descriptor.

The general consensus to avoid the deadlock is for the Wayland
compositor to never issue blocking X11 roundtrips, but in practice
blocking rountrips can occur in various places, including Xlib calls
themselves so this is not always achievable without major surgery in the
Wayland compositor/Window manager.

What this patch does is to avoid dispatching to the Wayland file
descriptor until it becomes available for writing again, while at the
same time continue processing X11 requests to release the deadlock.

This is not perfect, as there is still the possibility of another X
client hammering the connection and we'll still fail writing to the
Wayland connection eventually, but this improves things enough to avoid
a 100% repeatable crash with vlc and gtkperf.

Also, it is worth considering that window managers and Wayland
compositors such as mutter already have a higher priority than other
regular X clients thanks to XSyncSetPriority(), mitigating the risk.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1278159
Bugzilla: https://bugzilla.gnome.org/show_bug.cgi?id=763400
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
2016-09-28 14:23:59 -04:00
Xext Xext/shm: Fix usage of F_GETFD to match standard 2016-09-13 10:00:51 -07:00
Xi Hold input lock while calling input device SetProperty callback 2016-09-15 07:50:34 +10:00
composite Remove readmask from screen block/wakeup handler 2016-07-18 15:27:51 -04:00
config config/dbus: Initialize dbus fd to -1 so teardown doesn't use fd 0 2016-09-15 21:30:38 -07:00
damageext dix: Remove pointless client-state callbacks 2016-05-11 11:21:08 -04:00
dbe Convert top level extensions to new *allocarray functions 2015-04-21 16:57:08 -07:00
dix XQuartz: Adopt input_lock() and input_unlock() 2016-09-22 14:55:02 -07:00
doc Remove readmask from screen block/wakeup handler 2016-07-18 15:27:51 -04:00
dri3 dri3: Don't do return client->noClientException 2016-09-02 13:41:24 -04:00
exa Remove readmask from screen block/wakeup handler 2016-07-18 15:27:51 -04:00
fb Fix alphamap interactions with wfb 2015-09-29 12:21:34 -04:00
glamor glamor: Fall back to software for CopyPlane if we need to 2016-09-28 12:52:05 -04:00
glx Add Windows-DRI extension 2016-09-15 20:10:29 +01:00
hw xwayland: handle EAGAIN on Wayland fd 2016-09-28 14:23:59 -04:00
include dix: Silence TSan warnings when checking for pending input 2016-09-22 14:55:01 -07:00
m4 Add ax_pthread.m4 to m4/ 2016-05-29 19:20:51 -07:00
man Xserver.man: document more transports for -nolisten & -listen options 2015-10-28 14:16:28 -04:00
mi XQuartz: Adopt input_lock() and input_unlock() 2016-09-22 14:55:02 -07:00
miext Remove fd_set from Block/Wakeup handler API 2016-07-18 15:27:51 -04:00
os dix: Silence TSan warnings when checking for pending input 2016-09-22 14:55:01 -07:00
present present: Free the fake_present OsTimerPtr 2016-08-15 15:16:48 -04:00
pseudoramiX Convert top level extensions to new *allocarray functions 2015-04-21 16:57:08 -07:00
randr randr: Fix crtc_bounds when using rotation combined with reflection 2016-09-13 10:27:30 +02:00
record record: don't call RecordDeleteContext when AddResource fails 2016-03-08 10:20:04 -05:00
render exa: only draw valid trapezoids 2016-06-17 11:21:30 +02:00
test test: Run xts against Xephyr -glamor when present 2016-09-28 12:44:51 -04:00
xfixes dix: Remove pointless client-state callbacks 2016-05-11 11:21:08 -04:00
xkb xkb: fix turbo-repeat of RedirectKey-ed keysyms 2016-09-21 17:33:43 +10:00
.dir-locals.el Add .dir-locals.el 2013-08-17 12:17:36 +02:00
.gitignore .gitignore: Add new autotools file 'test-driver' 2014-04-21 13:41:42 -07:00
COPYING modesetting: Merge modesetting's COPYING into the xserver's. 2014-09-15 12:46:02 -07:00
Makefile.am DIST_SUBDIRS needs to include glamor, even if it isn't built 2014-02-13 15:25:56 -08:00
README packaging: provide a default README file #24206 2010-01-27 14:00:17 -08:00
autogen.sh autogen: Set a default subject prefix for patches 2016-02-08 17:41:38 -05:00
configure.ac Require xproto 7.0.31 2016-09-23 09:52:35 +03:00
devbook.am doc: Create a script to filter xmlto output 2015-01-05 14:24:06 -08:00
docbook.am docbook.am: embed css styles inside the HTML HEAD element 2011-09-21 14:07:49 -07:00
fix-miregion Change region implementation names to eliminate the 'mi' prefix 2010-06-05 17:47:32 -07:00
fix-miregion-private Change region implementation names to eliminate the 'mi' prefix 2010-06-05 17:47:32 -07:00
fix-patch-whitespace Rename region macros to eliminate screen argument 2010-06-05 18:59:00 -07:00
fix-region Rename region macros to eliminate screen argument 2010-06-05 18:59:00 -07:00
manpages.am Xorg: Add a suid root wrapper 2014-03-12 08:50:05 +01:00
xorg-server.m4 macros: clarify documentation 2012-11-05 13:24:57 -06:00
xorg-server.pc.in xfree86: link modules against Xorg symbols on Cygwin 2012-04-05 21:57:07 -05:00
xserver.ent.in doc: relocate xserver.ent in the package root directory 2011-05-14 11:22:26 -07:00

					X Server

The X server accepts requests from client applications to create windows,
which are (normally rectangular) "virtual screens" that the client program
can draw into.

Windows are then composed on the actual screen by the X server
(or by a separate composite manager) as directed by the window manager,
which usually communicates with the user via graphical controls such as buttons
and draggable titlebars and borders.

For a comprehensive overview of X Server and X Window System, consult the
following article:
http://en.wikipedia.org/wiki/X_server

All questions regarding this software should be directed at the
Xorg mailing list:

        http://lists.freedesktop.org/mailman/listinfo/xorg

Please submit bug reports to the Xorg bugzilla:

        https://bugs.freedesktop.org/enter_bug.cgi?product=xorg

The master development code repository can be found at:

        git://anongit.freedesktop.org/git/xorg/xserver

        http://cgit.freedesktop.org/xorg/xserver

For patch submission instructions, see:

	http://www.x.org/wiki/Development/Documentation/SubmittingPatches

For more information on the git code manager, see:

        http://wiki.x.org/wiki/GitPage