From: Brian Paul <bri...@vmware.com>
This is a follow-on to the previous commits. It seems that
XShmQueryVersion() can trigger an X error after the first X
connection is closed and we start using a new connection.
Fixes a bug found by Wayne E. Robertz.
NOTE: This is a candidate for the 7.11 branch.
---
src/mesa/drivers/x11/xm_api.c | 28 +++++++++++++++++++++++++++-
1 files changed, 27 insertions(+), 1 deletions(-)
diff --git a/src/mesa/drivers/x11/xm_api.c b/src/mesa/drivers/x11/xm_api.c
index 81b2459..8c0e783 100644
--- a/src/mesa/drivers/x11/xm_api.c
+++ b/src/mesa/drivers/x11/xm_api.c
@@ -105,6 +105,19 @@ static int host_byte_order( void )
}
+static GLboolean XShmErrorFlag;
+
+static int
+xshm_query_version_err_handler( XMesaDisplay* dpy, XErrorEvent* xerr )
+{
+ /* If this function gets called, it's because XShmQuerryVersion()
+ * has failed.
+ */
+ XShmErrorFlag = True;
+ return 0;
+}
+
+
/**
* Check if the X Shared Memory extension is available.
* Return: 0 = not available
@@ -118,7 +131,20 @@ static int check_for_xshm( XMesaDisplay *display )
Bool pixmaps;
if (XQueryExtension( display, "MIT-SHM", &ignore, &ignore, &ignore )) {
- if (XShmQueryVersion( display, &major, &minor, &pixmaps )==True) {
+ int (*old_handler)(XMesaDisplay *, XErrorEvent *);
+ int ok;
+
+ /* Install X error handler before calling XShmQueryVersion() to catch
+ * a spurious X error.
+ */
+ XShmErrorFlag = False;
+ old_handler = XSetErrorHandler(xshm_query_version_err_handler);
+ ok = XShmQueryVersion( display, &major, &minor, &pixmaps );
+ XSetErrorHandler(old_handler);
+ if (XShmErrorFlag)
+ ok = False;
+
+ if (ok) {
return (pixmaps==True) ? 2 : 1;
}
else {
--
1.7.1
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