[Intel-gfx] [PATCH 1/3] drm/i915: Handle YUV subpixel support better

[Maarten Lankhorst]

Y41x formats is a 4:4:4 format, so it can be addressed with pixel level accuracy.
Meanwhile it seems that while rotating YUYV 4:2:2 formats need a multiple of 2
for width and height, otherwise corruption occurs.

For YUV 4:2:2, the spec says that w/h should always be even, but we get
away with odd height while unrotated. When rotating it seems corruption
occurs with an odd x/y, and w/h should always be even.
Just to be completely paranoid, reject odd x/y w/h when rotating 90/270.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_sprite.c | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index 3f2055f70d05..aca987356194 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -269,7 +269,8 @@ int intel_plane_check_src_coordinates(struct intel_plane_state *plane_state)
 {
 	const struct drm_framebuffer *fb = plane_state->base.fb;
 	struct drm_rect *src = &plane_state->base.src;
-	u32 src_x, src_y, src_w, src_h;
+	u32 src_x, src_y, src_w, src_h, hsub, vsub;
+	bool rotated = drm_rotation_90_or_270(plane_state->base.rotation);
 
 	/*
 	 * Hardware doesn't handle subpixel coordinates.
@@ -287,18 +288,26 @@ int intel_plane_check_src_coordinates(struct intel_plane_state *plane_state)
 	src->y1 = src_y << 16;
 	src->y2 = (src_y + src_h) << 16;
 
-	if (fb->format->is_yuv &&
-	    (src_x & 1 || src_w & 1)) {
-		DRM_DEBUG_KMS("src x/w (%u, %u) must be a multiple of 2 for YUV planes\n",
-			      src_x, src_w);
+	if (!fb->format->is_yuv)
+		return 0;
+
+	/* YUV specific checks */
+	if (!rotated) {
+		hsub = fb->format->hsub;
+		vsub = fb->format->vsub;
+	} else {
+		hsub = vsub = max(fb->format->hsub, fb->format->vsub);
+	}
+
+	if (src_x % hsub || src_w % hsub) {
+		DRM_DEBUG_KMS("src x/w (%u, %u) must be a multiple of %u for %sYUV planes\n",
+			      src_x, src_w, hsub, rotated ? "rotated " : "");
 		return -EINVAL;
 	}
 
-	if (fb->format->is_yuv &&
-	    fb->format->num_planes > 1 &&
-	    (src_y & 1 || src_h & 1)) {
-		DRM_DEBUG_KMS("src y/h (%u, %u) must be a multiple of 2 for planar YUV planes\n",
-			      src_y, src_h);
+	if (src_y % vsub || src_h % vsub) {
+		DRM_DEBUG_KMS("src y/h (%u, %u) must be a multiple of %u for %sYUV planes\n",
+			      src_y, src_h, vsub, rotated ? "rotated " : "");
 		return -EINVAL;
 	}
 
-- 
2.20.1