drm: Reject stereo modes with an unknown layout

The kernel shouldn't accept invalid modes, just say No.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 7980f89..c2c4ace 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -58,6 +58,10 @@
 #define DRM_MODE_FLAG_PIXMUX			(1<<11)
 #define DRM_MODE_FLAG_DBLCLK			(1<<12)
 #define DRM_MODE_FLAG_CLKDIV2			(1<<13)
+ /*
+  * When adding a new stereo mode don't forget to adjust DRM_MODE_FLAGS_3D_MAX
+  * (define not exposed to user space).
+  */
 #define DRM_MODE_FLAG_3D_MASK			(0x1f<<14)
 #define  DRM_MODE_FLAG_3D_NONE			(0<<14)
 #define  DRM_MODE_FLAG_3D_FRAME_PACKING		(1<<14)