diff --git a/hw/xfree86/xaa/xaaGC.c b/hw/xfree86/xaa/xaaGC.c
index f3434c9f4..b3dc83ada 100644
--- a/hw/xfree86/xaa/xaaGC.c
+++ b/hw/xfree86/xaa/xaaGC.c
@@ -80,10 +80,11 @@ XAAValidateGC(
     }
 
     if(pGC->depth != 32) {
-	if(pGC->bgPixel == -1) /* -1 is reserved for transparency */
-	    pGC->bgPixel = 0x7fffffff; 
-	if(pGC->fgPixel == -1) /* -1 is reserved for transparency */
-	    pGC->fgPixel = 0x7fffffff; 
+	/* 0xffffffff is reserved for transparency */
+	if(pGC->bgPixel == 0xffffffff)
+	    pGC->bgPixel = 0x7fffffff;
+	if(pGC->fgPixel == 0xffffffff)
+	    pGC->fgPixel = 0x7fffffff;
     }
 
     if((pDraw->type == DRAWABLE_PIXMAP) && !IS_OFFSCREEN_PIXMAP(pDraw)){