On Mon Sep 28 19:50:45 2026 +0300, Michael Freidkin wrote:
> 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")
> Cc: [email protected]
> Signed-off-by: Michael Freidkin <[email protected]>
> Reviewed-by: Dan Carpenter <[email protected]>
> Signed-off-by: Nicolas Dufresne <[email protected]>
> Signed-off-by: Hans Verkuil <[email protected]>
Patch committed.
Thanks,
Hans Verkuil
drivers/staging/media/meson/vdec/vdec.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/drivers/staging/media/meson/vdec/vdec.c
b/drivers/staging/media/meson/vdec/vdec.c
index c18bf352b199..be29d5a11c2e 100644
--- a/drivers/staging/media/meson/vdec/vdec.c
+++ b/drivers/staging/media/meson/vdec/vdec.c
@@ -34,7 +34,7 @@ struct dummy_buf {
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)
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