intel: Correct value of S0_VB_OFFSET_MASK to match hardware docs.

diff --git a/src/mesa/drivers/dri/intel/intel_reg.h b/src/mesa/drivers/dri/intel/intel_reg.h
index d19f1ba..36d8180 100644 (file)
--- a/src/mesa/drivers/dri/intel/intel_reg.h
+++ b/src/mesa/drivers/dri/intel/intel_reg.h
@@ -70,8 +70,10 @@
 
 /** @{
  * 915 definitions
+ *
+ * 915 documents say that bits 31:28 and 1 are "undefined, must be zero."
  */
-#define S0_VB_OFFSET_MASK              0xffffffc0
+#define S0_VB_OFFSET_MASK              0x0ffffffc
 #define S0_AUTO_CACHE_INV_DISABLE      (1<<0)
 /** @} */