drm: Reject modes with more than 1 stereo flags set

When setting a stereo 3D mode, there can be only one bit set describing
the layout of the frambuffer(s). So reject invalid modes early.

Reviewed-by: Ville Syrjälä <[email protected]>
Signed-off-by: Damien Lespiau <[email protected]>
Acked-by: Dave Airlie <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 454ac8a6381cf590c7d2eff615df38c659c19a2a..090415f418b8eb2030ce0a79b90299187b4b2af3 100644 (file)
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -1319,6 +1319,10 @@ static int drm_crtc_convert_umode(struct drm_display_mode *out,
        if (in->clock > INT_MAX || in->vrefresh > INT_MAX)
                return -ERANGE;
 
+       /* At most, 1 set bit describing the 3D layout of the mode */
+       if (hweight32(in->flags & DRM_MODE_FLAG_3D_MASK) > 1)
+               return -EINVAL;
+
        out->clock = in->clock;
        out->hdisplay = in->hdisplay;
        out->hsync_start = in->hsync_start;