[Intel-gfx] [PATCH] drm/i915: Reject out-of-bound sprites

[Chris Wilson]

We make no attempt to fixup the source as we adjust the destination
rectangle, expect the caller to have already fixed that up. This makes
no sense, asking userspace to compensate for the kernel adjusting the
one rectangle not the other, so simply reject any attempt to show an
partially visible box. Userspace should know better.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_sprite.c |   31 ++++++-------------------------
 1 file changed, 6 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index 22d65f7..97866c2 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -498,31 +498,13 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 	}
 
 	/*
-	 * Clamp the width & height into the visible area.  Note we don't
-	 * try to scale the source if part of the visible region is offscreen.
-	 * The caller must handle that by adjusting source offset and size.
+	 * Reject any attempt to display video outside the visible area.
+	 * The caller must handle this by adjusting source offset and size.
 	 */
-	if ((crtc_x < 0) && ((crtc_x + crtc_w) > 0)) {
-		crtc_w += crtc_x;
-		crtc_x = 0;
-	}
-	if ((crtc_x + crtc_w) <= 0) /* Nothing to display */
-		goto out;
-	if ((crtc_x + crtc_w) > primary_w)
-		crtc_w = primary_w - crtc_x;
-
-	if ((crtc_y < 0) && ((crtc_y + crtc_h) > 0)) {
-		crtc_h += crtc_y;
-		crtc_y = 0;
-	}
-	if ((crtc_y + crtc_h) <= 0) /* Nothing to display */
-		goto out;
-	if (crtc_y + crtc_h > primary_h)
-		crtc_h = primary_h - crtc_y;
-
-	if (!crtc_w || !crtc_h) /* Again, nothing to display */
-		goto out;
-
+	if (crtc_x < 0 || crtc_x + crtc_w > primary_w)
+		return -EINVAL;
+	if (crtc_y < 0 || crtc_y + crtc_h > primary_h)
+		return -EINVAL;
 	/*
 	 * We may not have a scaler, eg. HSW does not have it any more
 	 */
@@ -571,7 +553,6 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 
 out_unlock:
 	mutex_unlock(&dev->struct_mutex);
-out:
 	return ret;
 }
 
-- 
1.7.10.4