glx: Work around X servers reporting bogus values of GLX_SWAP_METHOD_OML

[mesa.git] / src / glx / glxext.c

diff --git a/src/glx/glxext.c b/src/glx/glxext.c
index 9ef7ff5f694761b4c9a6eabb0ec89bdf0a40b009..9cbe334772391cc98ef5210b7b26bcd410aef1cc 100644 (file)
--- 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: