mesa-demos: fix deadlock in sharedtex_mt

This patch fixes a deadlock that occurs between the main
thread and rendering threads of the sharedtex_mt demo.

Signed-off-by: Awais Belal <awais_belal@mentor.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>

2 files changed, 44 insertions, 0 deletions

diff --git a/meta/recipes-graphics/mesa/mesa-demos/0010-sharedtex_mt-fix-rendering-thread-hang.patch b/meta/recipes-graphics/mesa/mesa-demos/0010-sharedtex_mt-fix-rendering-thread-hang.patch
new file mode 100644
index 0000000000..04e1b446f3
--- /dev/null
+++ b/meta/recipes-graphics/mesa/mesa-demos/0010-sharedtex_mt-fix-rendering-thread-hang.patch
@@ -0,0 +1,43 @@
+From 525fa9ded72d22b53c5eb366f61e2ac1d407a2db Mon Sep 17 00:00:00 2001
+From: Awais Belal <awais_belal@mentor.com>
+Date: Thu, 8 Oct 2015 13:49:31 +0500
+Subject: [PATCH] sharedtex_mt: fix rendering thread hang
+
+XNextEvent is a blocking call which locks up the display mutex
+this causes the rendering threads to hang when they try call
+glXSwapBuffers() as that tries to take the same mutex in
+underlying calls through XCopyArea().
+So we only go to XNextEvent when it has at least one event
+and we wouldn't lock indefinitely.
+
+Signed-off-by: Awais Belal <awais_belal@mentor.com>
+Upstream-Status: Backport (2b304e765695d385fd3bf414e6e444020bedb0a8)
+
+---
+ src/xdemos/sharedtex_mt.c | 9 +++++++--
+ 1 file changed, 7 insertions(+), 2 deletions(-)
+
+diff --git a/src/xdemos/sharedtex_mt.c b/src/xdemos/sharedtex_mt.c
+index a90903a..1d503c4 100644
+--- a/src/xdemos/sharedtex_mt.c
++++ b/src/xdemos/sharedtex_mt.c
+@@ -420,9 +420,14 @@ Resize(struct window *h, unsigned int width, unsigned int height)
+ static void
+ EventLoop(void)
+ {
++   int i;
++   XEvent event;
+    while (1) {
+-      int i;
+-      XEvent event;
++      /* Do we have an event? */
++      if (XPending(gDpy) == 0) {
++         usleep(10000);
++         continue;
++      }
+       XNextEvent(gDpy, &event);
+       for (i = 0; i < NumWindows; i++) {
+ 	 struct window *h = &Windows[i];
+-- 
+1.9.1
+
diff --git a/meta/recipes-graphics/mesa/mesa-demos_8.2.0.bb b/meta/recipes-graphics/mesa/mesa-demos_8.2.0.bb
index e4516425e2..0094f556f9 100644
--- a/meta/recipes-graphics/mesa/mesa-demos_8.2.0.bb
+++ b/meta/recipes-graphics/mesa/mesa-demos_8.2.0.bb
@@ -19,6 +19,7 @@ SRC_URI = "ftp://ftp.freedesktop.org/pub/mesa/demos/${PV}/${BPN}-${PV}.tar.bz2 \
     file://0007-Install-few-more-test-programs.patch \
     file://0008-glsl-perf-Add-few-missing-.glsl-.vert-.frag-files-to.patch \
     file://0009-glsl-perf-Install-.glsl-.vert-.frag-files.patch \
+    file://0010-sharedtex_mt-fix-rendering-thread-hang.patch \
 "
 SRC_URI[md5sum] = "72613a2c8c013716db02e3ff59d29061"
 SRC_URI[sha256sum] = "e4bfecb5816ddd4b7b37c1bc876b63f1f7f06fda5879221a9774d0952f90ba92"