drm/udl: limit modes to the sku pixel limits.
Otherwise when X starts we commonly get a black screen scanning
out nothing, its wierd dpms on/off from userspace brings it back,
With this on F18, multi-seat works again with my 1920x1200 monitor
which is above the sku limit for the device I have.
Cc: stable@vger.kernel.org
Reviewed-by: Alex Deucher <alexander.deucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/udl/udl_connector.c b/drivers/gpu/drm/udl/udl_connector.c
index ba055e9..8d9dc44 100644
--- a/drivers/gpu/drm/udl/udl_connector.c
+++ b/drivers/gpu/drm/udl/udl_connector.c
@@ -69,6 +69,13 @@
static int udl_mode_valid(struct drm_connector *connector,
struct drm_display_mode *mode)
{
+ struct udl_device *udl = connector->dev->dev_private;
+ if (!udl->sku_pixel_limit)
+ return 0;
+
+ if (mode->vdisplay * mode->hdisplay > udl->sku_pixel_limit)
+ return MODE_VIRTUAL_Y;
+
return 0;
}