diff --git a/drivers/gpu/drm/gma500/psb_drv.h b/drivers/gpu/drm/gma500/psb_drv.h
index 0bab46bd73d234d6757237eea9a912a603f8ec4a..b26d029a2e814d2277253b18bd119e0f9f3d9cdd 100644
--- a/drivers/gpu/drm/gma500/psb_drv.h
+++ b/drivers/gpu/drm/gma500/psb_drv.h
@@ -45,7 +45,7 @@ enum {
 };
 
 #define IS_PSB(dev) (((dev)->pdev->device & 0xfffe) == 0x8108)
-#define IS_MRST(dev) (((dev)->pdev->device & 0xfffc) == 0x4100)
+#define IS_MRST(dev) (((dev)->pdev->device & 0xfff0) == 0x4100)
 #define IS_MFLD(dev) (((dev)->pdev->device & 0xfff8) == 0x0130)
 #define IS_CDV(dev) (((dev)->pdev->device & 0xfff0) == 0x0be0)