[PATCH] drm/vkms: Fix vertical read step for R1/R2/R4 formats

[oushixiong1025]

From: Shixiong Ou <oushixiong@xxxxxxxxxx>

get_block_step_bytes() returns pitches * block_w as the vertical step for
READ_TOP_TO_BOTTOM and READ_BOTTOM_TO_TOP, but consecutive rows are
pitches * block_h bytes apart (block_h is 1 for R1/R2/R4). Vertical reads
therefore sample every block_w-th row instead of every row, and walk past
the end of the framebuffer, when 90/270-rotating or reflecting R1/R2/R4
planes. Use the block height instead, matching packed_pixels_offset().

Signed-off-by: Shixiong Ou <oushixiong@xxxxxxxxxx>
---
 drivers/gpu/drm/vkms/vkms_formats.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
index dfb8e13cba87..1e3a6af9cea5 100644
--- a/drivers/gpu/drm/vkms/vkms_formats.c
+++ b/drivers/gpu/drm/vkms/vkms_formats.c
@@ -103,11 +103,11 @@ static int get_block_step_bytes(struct drm_framebuffer *fb, enum pixel_read_dire
 	case READ_RIGHT_TO_LEFT:
 		return -fb->format->char_per_block[plane_index];
 	case READ_TOP_TO_BOTTOM:
-		return (int)fb->pitches[plane_index] * drm_format_info_block_width(fb->format,
-										   plane_index);
-	case READ_BOTTOM_TO_TOP:
-		return -(int)fb->pitches[plane_index] * drm_format_info_block_width(fb->format,
+		return (int)fb->pitches[plane_index] * drm_format_info_block_height(fb->format,
 										    plane_index);
+	case READ_BOTTOM_TO_TOP:
+		return -(int)fb->pitches[plane_index] * drm_format_info_block_height(fb->format,
+										     plane_index);
 	}
 
 	return 0;
-- 
2.25.1


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