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XLibre Xserver
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Eric Anholt 77e51d5bbb Revert "DRI2: re-allocate DRI2 drawable if pixmap serial changes" 
This reverts commit 3209b094a3.  After a
long debug session by Paul Berry, it appears that this was the commit
that has been producing sporadic failures in piglit front buffer
rendering tests for the last several years.

GetBuffers may return fresh buffers with invalid contents at a couple
reasonable times:

- When first asked for a non-fake-front buffer.
- When the drawable size is changed, an Invalidate has been sent, and
  obviously the app needs to redraw the whole buffer.
- After a glXSwapBuffers(), GL allows the backbuffer to be undefined,
  and an Invalidate was sent to tell the GL that it should grab these
  appropriate new buffers to avoid stalling.

But with the patch being reverted, GetBuffers would also return fresh
invalid buffers when the drawable serial number changed, which is
approximately "whenever, for any reason".  The app is not expecting
invalid buffer contents "whenever", nor is it valid.  Because the GL
usually only GetBuffers after an Invalidate is sent, and the new
buffer allocation only happened during a GetBuffers, most apps saw no
problems.  But apps that do (fake-)frontbuffer rendering do frequently
ask the server for the front buffer (since we drop the fake front
allocation when we're not doing front buffer rendering), and if the
drawable serial got bumped midway through a draw, the server would
pointlessly ditch the front *and* backbuffer full of important
drawing, resulting in bad rendering.

The patch was originally to fix bugzilla:
https://bugs.freedesktop.org/show_bug.cgi?id=28365
Specifically:

    To reproduce, start with a large-ish display (i.e. 1680x1050 on my
    laptop), use the patched glxgears from bug 28252 to add the
    -override option.  Then run glxgears -override -geometry 640x480
    to create a 640x480 window in the top left corner, which will work
    fine.  Next, run xrandr -s 640x480 and watch the fireworks.

I've tested with an override-redirect glxgears, both with vblank sync
enabled and disabled, both with gnome-shell and no window manager at
all, before and after this patch.  The only problem observed was that
before and after the revert, sometimes when alt-tabbing to kill my
gears after completing the test gnome-shell would get confused about
override-redirectness of the glxgears window (according to a log
message) and apparently not bother doing any further compositing.

Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Keith Packard <keithp@keithp.com>
 		2013-06-18 10:54:22 -07:00
Xext Abstract cursor refcounting 2013-05-15 19:17:57 +10:00
Xi Xi: fix warning - remove unused 'rc' 2013-05-15 19:17:39 +10:00
composite Stop leaking overlayWin in PanoramiXCompositeGetOverlayWindow error paths 2013-02-05 18:30:13 -08:00
config config: add a quirks file for devices needing special configuration 2013-06-06 08:12:42 +10:00
damageext Move extension initialisation prototypes into extinit.h 2012-07-09 23:06:41 -07:00
dbe Move extension initialisation prototypes into extinit.h 2012-07-09 23:06:41 -07:00
dix dix: remove logspam in RefCursor() 2013-05-26 22:41:31 -06:00
doc doc: Update documentation about Windows platforms support a bit 2012-10-29 12:21:14 +00:00
exa Fix formatting of address operators 2012-12-05 18:09:48 -06:00
fb dix: allow pixmap dirty helper to be used for non-shared pixmaps 2013-04-30 10:10:31 +10:00
glx os: Use ErrorFSigSafe from FatalError and it's friends 2013-05-07 09:41:14 +10:00
hw Revert "DRI2: re-allocate DRI2 drawable if pixmap serial changes" 2013-06-18 10:54:22 -07:00
include dix: add missing dixFreeRegistry define 2013-06-06 08:12:38 +10:00
m4 XORG_TLS: Pick the first option that works (ie: prefer __thread) 2013-02-14 09:20:47 -08:00
man Correct description of -displayfd option in man page. 2012-10-11 12:53:57 +01:00
mi mi: Ensure pointer emulating touch events update the sprite 2013-01-09 11:23:06 +10:00
miext Shadow: Switch the Amiga/Atari bitplane code to the canonical X.Org license 2013-05-14 14:41:00 -07:00
os os: Reset input buffer's 'ignoreBytes' field 2013-05-10 09:02:57 +10:00
randr randr: only respected changed on the protocol screen 2013-04-30 10:08:43 +10:00
record Move extension initialisation prototypes into extinit.h 2012-07-09 23:06:41 -07:00
render Abstract cursor refcounting 2013-05-15 19:17:57 +10:00
test os: complain about unsupported pnprintf directives 2013-05-07 09:41:11 +10:00
xfixes Abstract cursor refcounting 2013-05-15 19:17:57 +10:00
xkb input: print warnings if drivers don't initialize properly 2013-05-10 11:05:00 +10:00
.gitignore doc: relocate xserver.ent in the package root directory 2011-05-14 11:22:26 -07:00
COPYING Shadow: Switch the Amiga/Atari bitplane code to the canonical X.Org license 2013-05-14 14:41:00 -07:00
Makefile.am Add 'install-headers' target in the top-level Makefile 2012-07-09 16:29:04 -07:00
README packaging: provide a default README file #24206 2010-01-27 14:00:17 -08:00
autogen.sh autogen.sh: Honor NOCONFIGURE=1 2012-10-19 13:12:33 +10:00
configure.ac If neither HAL nor udev backends are enabled, warn the user 2013-05-07 09:40:46 +10:00
devbook.am devbook.am: maintenance update from docbook.am 2011-09-21 14:07:52 -07:00
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 Xdmx.man: Show actual configured XKB defaults instead of old hardcoded values 2011-06-21 17:54:14 -07:00
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

README 

					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