DRI2: Add interface for drivers to query DRI2 extension version

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>

2 files changed, 27 insertions, 0 deletions

diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
index 0b52a0f8c..80de18f86 100644
--- a/hw/xfree86/dri2/dri2.c
+++ b/hw/xfree86/dri2/dri2.c
@@ -380,3 +380,12 @@ static XF86ModuleVersionInfo DRI2VersRec =
 
 _X_EXPORT XF86ModuleData dri2ModuleData = { &DRI2VersRec, DRI2Setup, NULL };
 
+void
+DRI2Version(int *major, int *minor)
+{
+    if (major != NULL)
+	*major = DRI2VersRec.majorversion;
+
+    if (minor != NULL)
+	*minor = DRI2VersRec.minorversion;
+}
diff --git a/hw/xfree86/dri2/dri2.h b/hw/xfree86/dri2/dri2.h
index 847e57c68..9d7d6dc80 100644
--- a/hw/xfree86/dri2/dri2.h
+++ b/hw/xfree86/dri2/dri2.h
@@ -100,4 +100,22 @@ extern _X_EXPORT int DRI2CopyRegion(DrawablePtr pDraw,
 		   unsigned int dest,
 		   unsigned int src);
 
+/**
+ * Determine the major and minor version of the DRI2 extension.
+ *
+ * Provides a mechanism to other modules (e.g., 2D drivers) to determine the
+ * version of the DRI2 extension.  While it is possible to peek directly at
+ * the \c XF86ModuleData from a layered module, such a module will fail to
+ * load (due to an unresolved symbol) if the DRI2 extension is not loaded.
+ *
+ * \param major  Location to store the major verion of the DRI2 extension
+ * \param minor  Location to store the minor verion of the DRI2 extension
+ *
+ * \note
+ * This interface was added some time after the initial release of the DRI2
+ * module.  Layered modules that wish to use this interface must first test
+ * its existance by calling \c xf86LoaderCheckSymbol.
+ */
+extern _X_EXPORT void DRI2Version(int *major, int *minor);
+
 #endif