drm/plane-helper: Fix primary plane scaling check

The src_w / src_h parameters to update_plane include a subpixel offset;
we need to shift off the subpixel bits before comparing to CRTC size
when checking for primary plane scaling.

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_plane_helper.c b/drivers/gpu/drm/drm_plane_helper.c
index d2b1c03b3d71..f48566445c31 100644
--- a/drivers/gpu/drm/drm_plane_helper.c
+++ b/drivers/gpu/drm/drm_plane_helper.c
@@ -145,6 +145,8 @@ int drm_primary_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
         }
 
         /* Disallow scaling */
+        src_w >>= 16;
+        src_h >>= 16;
         if (crtc_w != src_w || crtc_h != src_h) {
                 DRM_DEBUG_KMS("Can't scale primary plane\n");
                 return -EINVAL;