2022-04-01 10:02:49

by Nicolas Dufresne

Subject: [PATCH v2 02/23] media: v4l2-mem2mem: Trace on implicit un-hold

If the timestamp of the src buffer differs from the timestamp of a held
dst buffer, the held buffer is implicitly removed and marked as done.
Add a trace to help debugging if someone hits that case.

Signed-off-by: Nicolas Dufresne <[email protected]>
Reviewed-by: Sebastian Fricke <[email protected]>
---
drivers/media/v4l2-core/v4l2-mem2mem.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c
index 675e22895ebe..fbcd79763e8f 100644
--- a/drivers/media/v4l2-core/v4l2-mem2mem.c
+++ b/drivers/media/v4l2-core/v4l2-mem2mem.c
@@ -336,6 +336,7 @@ static void __v4l2_m2m_try_queue(struct v4l2_m2m_dev *m2m_dev,
if (src && dst && dst->is_held &&
dst->vb2_buf.copied_timestamp &&
dst->vb2_buf.timestamp != src->vb2_buf.timestamp) {
+ dprintk("src and dst timestamp mismatch, removing held capture buffer.\n");
dst->is_held = false;
v4l2_m2m_dst_buf_remove(m2m_ctx);
v4l2_m2m_buf_done(dst, VB2_BUF_STATE_DONE);
--
2.34.1

2022-04-02 17:08:08

by Ezequiel Garcia

Subject: Re: [PATCH v2 02/23] media: v4l2-mem2mem: Trace on implicit un-hold

On Thu, Mar 31, 2022 at 03:37:04PM -0400, Nicolas Dufresne wrote:
> If the timestamp of the src buffer differs from the timestamp of a held
> dst buffer, the held buffer is implicitly removed and marked as done.
> Add a trace to help debugging if someone hits that case.
>
> Signed-off-by: Nicolas Dufresne <[email protected]>
> Reviewed-by: Sebastian Fricke <[email protected]>
> ---
> drivers/media/v4l2-core/v4l2-mem2mem.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c
> index 675e22895ebe..fbcd79763e8f 100644
> --- a/drivers/media/v4l2-core/v4l2-mem2mem.c
> +++ b/drivers/media/v4l2-core/v4l2-mem2mem.c
> @@ -336,6 +336,7 @@ static void __v4l2_m2m_try_queue(struct v4l2_m2m_dev *m2m_dev,
> if (src && dst && dst->is_held &&
> dst->vb2_buf.copied_timestamp &&
> dst->vb2_buf.timestamp != src->vb2_buf.timestamp) {
> + dprintk("src and dst timestamp mismatch, removing held capture buffer.\n");

Nitpick: I would try to make this log consistent with the other logs,
avoid refering to "src" and "dst" and start with a capital letter.

How about "Timestamp mismatch, returning held capture buffer".

Either way, thanks for improving this.

Reviewed-by: Ezequiel Garcia <[email protected]>

> dst->is_held = false;
> v4l2_m2m_dst_buf_remove(m2m_ctx);
> v4l2_m2m_buf_done(dst, VB2_BUF_STATE_DONE);
> --
> 2.34.1
>