[Mesa-dev] [PATCH 2/4] glx: Work around X servers reporting bogus values of GLX_SWAP_METHOD_OML

[Thomas Hellstrom]

Due to the recently fixed bug where dri drivers didn't report a correct
__DRI_ATTRIB_SWAP_METHOD value, and the fact that X servers just forward this
incorrect value (from the AIGLX dri driver) untranslated as
GLX_SWAP_METHOD_OML, the latter value might be undefined when old dri AIGLX
values are used, which breaks client fbconfig matching with server fbconfigs.

So work around this by assuming GLX_SWAP_METHOD_UNDEFINED when a bogus value
is read.

Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
---
 src/glx/glxext.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/glx/glxext.c b/src/glx/glxext.c
index 9ef7ff5..9cbe334 100644
--- a/src/glx/glxext.c
+++ b/src/glx/glxext.c
@@ -524,7 +524,17 @@ __glXInitializeVisualConfigFromTags(struct glx_config * config, int count,
          config->visualSelectGroup = *bp++;
          break;
       case GLX_SWAP_METHOD_OML:
-         config->swapMethod = *bp++;
+         if (*bp == GLX_SWAP_UNDEFINED_OML ||
+             *bp == GLX_SWAP_COPY_OML ||
+             *bp == GLX_SWAP_EXCHANGE_OML) {
+            config->swapMethod = *bp++;
+         } else {
+            /* X servers with old HW drivers may return any value here, so
+             * assume GLX_SWAP_METHOD_UNDEFINED.
+             */
+            config->swapMethod = GLX_SWAP_UNDEFINED_OML;
+            bp++;
+         }
          break;
 #endif
       case GLX_SAMPLE_BUFFERS_SGIS:
-- 
2.7.4