drm/radeon/kms: don't enable underscan with interlaced modes

They aren't compatible.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index 8c987c9..127a395f 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -1151,6 +1151,7 @@
 
 			/* fix up for overscan on hdmi */
 			if (ASIC_IS_AVIVO(rdev) &&
+			    (!(mode->flags & DRM_MODE_FLAG_INTERLACE)) &&
 			    ((radeon_encoder->underscan_type == UNDERSCAN_ON) ||
 			     ((radeon_encoder->underscan_type == UNDERSCAN_AUTO) &&
 			      drm_detect_hdmi_monitor(radeon_connector->edid) &&