[PATCH v2 3/4] drm/rect: Keep the clipped dst rectangle in place

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Now that we've constrained the clipped source rectangle such
that it can't have negative dimensions doing the same for the
dst rectangle seems appropriate. Should at least result in
the clipped src and dst rectangles being a bit more consistent
with each other.

Cc: Benjamin Gaignard <benjamin.gaignard at st.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/drm_rect.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/drm_rect.c b/drivers/gpu/drm/drm_rect.c
index a9c7f90836f3..1e1e2101007a 100644
--- a/drivers/gpu/drm/drm_rect.c
+++ b/drivers/gpu/drm/drm_rect.c
@@ -52,7 +52,7 @@ bool drm_rect_intersect(struct drm_rect *r1, const struct drm_rect *r2)
 }
 EXPORT_SYMBOL(drm_rect_intersect);
 
-static u32 clip_scaled(u32 src, u32 dst, u32 clip)
+static u32 clip_scaled(int src, int dst, int *clip)
 {
 	u64 tmp;
 
@@ -60,9 +60,9 @@ static u32 clip_scaled(u32 src, u32 dst, u32 clip)
 		return 0;
 
 	/* Only clip what we have. Keeps the result bounded. */
-	clip = min(clip, dst);
+	*clip = min(*clip, dst);
 
-	tmp = mul_u32_u32(src, dst - clip);
+	tmp = mul_u32_u32(src, dst - *clip);
 
 	/*
 	 * Round toward 1.0 when clipping so that we don't accidentally
@@ -95,34 +95,34 @@ bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
 	diff = clip->x1 - dst->x1;
 	if (diff > 0) {
 		u32 new_src_w = clip_scaled(drm_rect_width(src),
-					    drm_rect_width(dst), diff);
+					    drm_rect_width(dst), &diff);
 
 		src->x1 = src->x2 - new_src_w;
-		dst->x1 = clip->x1;
+		dst->x1 += diff;
 	}
 	diff = clip->y1 - dst->y1;
 	if (diff > 0) {
 		u32 new_src_h = clip_scaled(drm_rect_height(src),
-					    drm_rect_height(dst), diff);
+					    drm_rect_height(dst), &diff);
 
 		src->y1 = src->y2 - new_src_h;
-		dst->y1 = clip->y1;
+		dst->y1 += diff;
 	}
 	diff = dst->x2 - clip->x2;
 	if (diff > 0) {
 		u32 new_src_w = clip_scaled(drm_rect_width(src),
-					    drm_rect_width(dst), diff);
+					    drm_rect_width(dst), &diff);
 
 		src->x2 = src->x1 + new_src_w;
-		dst->x2 = clip->x2;
+		dst->x2 -= diff;
 	}
 	diff = dst->y2 - clip->y2;
 	if (diff > 0) {
 		u32 new_src_h = clip_scaled(drm_rect_height(src),
-					    drm_rect_height(dst), diff);
+					    drm_rect_height(dst), &diff);
 
 		src->y2 = src->y1 + new_src_h;
-		dst->y2 = clip->y2;
+		dst->y2 -= diff;
 	}
 
 	return drm_rect_visible(dst);
-- 
2.23.0