Add one API to allow the user to specify the loaded backend driver

Sometimes there exist multiple backend vaapi drivers on one system. In such case
user hopes to load the specific driver based on the request. Currently it can
be specified by using LIBVA_DRIVER_NAME environment. But it is not convenient.
So one API is added to allow the user to specify the loaded backend vaapi driver.
And it is called by using the following sequence:
   >vaGetDisplay(
   >vaSetDriverName(va_dpy, driver_name)
   >vaInitialize

V1->V2: Use the reserved space to store override_driver_name based on Haihao's
suggestion.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/va/va.h b/va/va.h
index 83d633f..88fde4e 100644
--- a/va/va.h
+++ b/va/va.h
@@ -232,7 +232,14 @@ const char *vaErrorStr(VAStatus error_status);
 typedef void* VANativeDisplay;	/* window system dependent */
 
 int vaDisplayIsValid(VADisplay dpy);
-    
+
+/**
+ *  Set the override driver name instead of queried driver driver.
+ */
+VAStatus vaSetDriverName(VADisplay dpy,
+                         char *driver_name
+);
+
 /**
  * Initialize the library 
  */