diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 85037b9d4934d406306634c486ed93cc92b771f3..5033c74966aae2c0473da1af3d5ebf4d1aa8ee3c 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -866,8 +866,12 @@ static void intel_sdvo_get_mode_from_dtd(struct drm_display_mode * mode,
 		mode->flags |= DRM_MODE_FLAG_INTERLACE;
 	if (dtd->part2.dtd_flags & DTD_FLAG_HSYNC_POSITIVE)
 		mode->flags |= DRM_MODE_FLAG_PHSYNC;
+	else
+		mode->flags |= DRM_MODE_FLAG_NHSYNC;
 	if (dtd->part2.dtd_flags & DTD_FLAG_VSYNC_POSITIVE)
 		mode->flags |= DRM_MODE_FLAG_PVSYNC;
+	else
+		mode->flags |= DRM_MODE_FLAG_NVSYNC;
 }
 
 static bool intel_sdvo_check_supp_encode(struct intel_sdvo *intel_sdvo)