[PATCH] glx: Add support for the new DRI loader entrypoint.

[Eric Anholt]

This is going to be exposed (and not the old entrypoint) for some DRI
drivers once the megadrivers series lands, and the plan is to
eventually transition all drivers to that.  Hopefully this is
unobtrusive enough to merge to stable X servers so that they can be
compatible with new Mesa versions.

v2: typo fix in the comment

Signed-off-by: Eric Anholt <eric at anholt.net>
Reviewed-by: Adam Jackson <ajax at redhat.com>
---
 glx/glxdricommon.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/glx/glxdricommon.c b/glx/glxdricommon.c
index b027f24..0ab3e30 100644
--- a/glx/glxdricommon.c
+++ b/glx/glxdricommon.c
@@ -211,6 +211,14 @@ glxConvertConfigs(const __DRIcoreExtension * core,
 
 static const char dri_driver_path[] = DRI_DRIVER_PATH;
 
+/* Temporary define to allow building without a dri_interface.h from
+ * updated Mesa.  Some day when we don't care about Mesa that old any
+ * more this can be removed.
+ */
+#ifndef __DRI_DRIVER_GET_EXTENSIONS
+#define __DRI_DRIVER_GET_EXTENSIONS "__driDriverGetExtensions"
+#endif
+
 void *
 glxProbeDriver(const char *driverName,
                void **coreExt, const char *coreName, int coreVersion,
@@ -219,7 +227,8 @@ glxProbeDriver(const char *driverName,
     int i;
     void *driver;
     char filename[PATH_MAX];
-    const __DRIextension **extensions;
+    char *get_extensions_name;
+    const __DRIextension **extensions = NULL;
 
     snprintf(filename, sizeof filename, "%s/%s_dri.so",
              dri_driver_path, driverName);
@@ -231,7 +240,18 @@ glxProbeDriver(const char *driverName,
         goto cleanup_failure;
     }
 
-    extensions = dlsym(driver, __DRI_DRIVER_EXTENSIONS);
+    if (asprintf(&get_extensions_name, "%s_%s",
+                 __DRI_DRIVER_GET_EXTENSIONS, driverName) != -1) {
+        const __DRIextension **(*get_extensions)(void);
+
+        get_extensions = dlsym(driver, get_extensions_name);
+        if (get_extensions)
+            extensions = get_extensions();
+        free(get_extensions_name);
+    }
+
+    if (!extensions)
+        extensions = dlsym(driver, __DRI_DRIVER_EXTENSIONS);
     if (extensions == NULL) {
         LogMessage(X_ERROR, "AIGLX error: %s exports no extensions (%s)\n",
                    driverName, dlerror());
-- 
1.8.4.rc3