drm/radeon: R300 AD only has one quad pipe.

Gleaned from the Mesa code.

Fixes https://bugs.freedesktop.org/show_bug.cgi?id=27355 .

Signed-off-by: Michel Dänzer <daenzer@vmware.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r300.c b/drivers/gpu/drm/radeon/r300.c
index 1023eeb..0e9eb76 100644
--- a/drivers/gpu/drm/radeon/r300.c
+++ b/drivers/gpu/drm/radeon/r300.c
@@ -324,11 +324,12 @@
 
 	r100_hdp_reset(rdev);
 	/* FIXME: rv380 one pipes ? */
-	if ((rdev->family == CHIP_R300) || (rdev->family == CHIP_R350)) {
+	if ((rdev->family == CHIP_R300 && rdev->pdev->device != 0x4144) ||
+	    (rdev->family == CHIP_R350)) {
 		/* r300,r350 */
 		rdev->num_gb_pipes = 2;
 	} else {
-		/* rv350,rv370,rv380 */
+		/* rv350,rv370,rv380,r300 AD */
 		rdev->num_gb_pipes = 1;
 	}
 	rdev->num_z_pipes = 1;