9ae84ad187
To prevent different threads from stealing the socket from each other the caller of "xcb_take_socket" must hold a lock that is also acquired in "return_socket". Unfortunately xcb tries to prevent calling return_socket from multiple threads and this can lead to a deadlock situation. A simple example: - X11 has taken the socket - Thread A has locked the display. - Thread B does xcb_no_operation() and thus ends up in libX11's return_socket(), waiting for the display lock. - Thread A calls e.g. xcb_no_operation(), too, ends up in return_socket() and because socket_moving == 1, ends up waiting for thread B => Deadlock This patch allows calling return_socket from different threads at the same time an so resolves the deadlock situation. Partially fixes: https://bugs.freedesktop.org/show_bug.cgi?id=20708 v2: fixes additional pthread_cond_wait dependencies, rework comments and patch description v3: separate pthread_cond_wait dependencies and unrelated whitespace change into their own patch, use unsigned for socket_seq Signed-off-by: Christian König <christian.koenig@amd.com> Signed-off-by: Uli Schlachter <psychon@znc.in> |
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|---|---|---|
| doc | ||
| src | ||
| tests | ||
| tools | ||
| .gitignore | ||
| COPYING | ||
| INSTALL | ||
| Makefile.am | ||
| NEWS | ||
| README | ||
| acinclude.m4 | ||
| autogen.sh | ||
| configure.ac | ||
| xcb-composite.pc.in | ||
| xcb-damage.pc.in | ||
| xcb-dpms.pc.in | ||
| xcb-dri2.pc.in | ||
| xcb-glx.pc.in | ||
| xcb-randr.pc.in | ||
| xcb-record.pc.in | ||
| xcb-render.pc.in | ||
| xcb-res.pc.in | ||
| xcb-screensaver.pc.in | ||
| xcb-shape.pc.in | ||
| xcb-shm.pc.in | ||
| xcb-sync.pc.in | ||
| xcb-xevie.pc.in | ||
| xcb-xf86dri.pc.in | ||
| xcb-xfixes.pc.in | ||
| xcb-xinerama.pc.in | ||
| xcb-xinput.pc.in | ||
| xcb-xkb.pc.in | ||
| xcb-xprint.pc.in | ||
| xcb-xselinux.pc.in | ||
| xcb-xtest.pc.in | ||
| xcb-xv.pc.in | ||
| xcb-xvmc.pc.in | ||
| xcb.pc.in | ||
About libxcb
============
libxcb provides an interface to the X Window System protocol, which
replaces the current Xlib interface. It has several advantages over
Xlib, including:
- size: small, simple library, and lower memory footprint
- latency hiding: batch several requests and wait for the replies later
- direct protocol access: interface and protocol correspond exactly
- proven thread support: transparently access XCB from multiple threads
- easy extension implementation: interfaces auto-generated from XML-XCB
Xlib can also use XCB as a transport layer, allowing software to make
requests and receive responses with both, which eases porting to XCB.
However, client programs, libraries, and toolkits will gain the most
benefit from a native XCB port.
Please report any issues you find to the freedesktop.org bug tracker,
at:
<https://bugs.freedesktop.org/enter_bug.cgi?product=XCB>
Discussion about XCB occurs on the XCB mailing list:
<mailto:xcb at lists.freedesktop.org>
<http://lists.freedesktop.org/mailman/listinfo/xcb>
You can obtain the latest development versions of XCB using GIT.
For anonymous checkouts, use:
git clone git://anongit.freedesktop.org/git/xcb/libxcb
For developers, use:
git clone git+ssh://git.freedesktop.org/git/xcb/libxcb