[PATCH] media: meson: vdec: size capture planes from the aligned canvas

[Michael Freidkin]

The decoder writes a whole canvas of ALIGN(width, 32) x ALIGN(height, 32)
(amvdec_set_canvases()) and reports bytesperline = ALIGN(width, 32), but
get_output_size() derives sizeimage from the raw width x height.

When the width is not a multiple of 32 the planes are too small for the
advertised stride: for 720x360 NV12M the luma plane is 262144 bytes while
736 * 360 = 264960 are needed (282624 for the canvas the firmware fills).
The decoder writes past the buffer, and importing the capture dma-buf
into DRM fails: drmModeAddFB2() returns -EINVAL, so e.g. Kodi plays the
sound over a black screen. 1280x720 and 1920x1080 are not affected.

Size the planes from the aligned canvas the hardware actually uses.

Tested on an S905X (GXL p212) board with LibreELEC 12 (6.16.0-rc3):
720x360 and 1920x1080 H.264 play through V4L2 m2m + DRM PRIME with no
AddFB2 errors.

Fixes: 3e7f51bd9607 ("media: meson: add v4l2 m2m video decoder driver")
Signed-off-by: Michael Freidkin <freidkin@xxxxxxxxx>
---
 drivers/staging/media/meson/vdec/vdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/staging/media/meson/vdec/vdec.c
+++ b/drivers/staging/media/meson/vdec/vdec.c
@@ -34,7 +34,7 @@
 
 static u32 get_output_size(u32 width, u32 height)
 {
-	return ALIGN(width * height, SZ_64K);
+	return ALIGN(ALIGN(width, 32) * ALIGN(height, 32), SZ_64K);
 }
 
 u32 amvdec_get_output_size(struct amvdec_session *sess)
--