[PATCHv7 03/15] v4l: vb2: add support for shared buffer (dma_buf)

[Dima Zavin]

ping?

On Tue, Jun 19, 2012 at 11:12 PM, Dima Zavin <dmitriyz at google.com> wrote:

> Tomasz,
>
> I've encountered an issue with this patch when userspace does several
> stream_on/stream_off cycles. When the user tries to qbuf a buffer
> after doing stream_off, we trigger the "dmabuf already pinned" warning
> since we didn't unmap the buffer as dqbuf was never called.
>
> The below patch adds calls to unmap in queue_cancel, but my feeling is
> that we
> probably should be calling detach too (i.e. put_dmabuf).
>
> Thoughts?
>
> --Dima
>
> Subject: [PATCH] v4l: vb2: unmap dmabufs on STREAM_OFF event
>
> Currently, if the user issues a STREAM_OFF request and then
> tries to re-enqueue buffers, it will trigger a warning in
> the vb2 allocators as the buffer would still be mapped
> from before STREAM_OFF was called. The current expectation
> is that buffers will be unmapped in dqbuf, but that will never
> be called on the mapped buffers after a STREAM_OFF event.
>
> Cc: Sumit Semwal <sumit.semwal at ti.com>
> Cc: Tomasz Stanislawski <t.stanislaws at samsung.com>
> Signed-off-by: Dima Zavin <dima at android.com>
> ---
>  drivers/media/video/videobuf2-core.c |   22 ++++++++++++++++++++--
>  1 files changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/video/videobuf2-core.c
> b/drivers/media/video/videobuf2-core.c
> index b431dc6..e2a8f12 100644
> --- a/drivers/media/video/videobuf2-core.c
> +++ b/drivers/media/video/videobuf2-core.c
> @@ -1592,8 +1592,26 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
>        /*
>         * Reinitialize all buffers for next use.
>         */
> -       for (i = 0; i < q->num_buffers; ++i)
> -               q->bufs[i]->state = VB2_BUF_STATE_DEQUEUED;
> +       for (i = 0; i < q->num_buffers; ++i) {
> +               struct vb2_buffer *vb = q->bufs[i];
> +               int plane;
> +
> +               vb->state = VB2_BUF_STATE_DEQUEUED;
> +
> +               if (q->memory != V4L2_MEMORY_DMABUF)
> +                       continue;
> +
> +               for (plane = 0; plane < vb->num_planes; ++plane) {
> +                       struct vb2_plane *p = &vb->planes[plane];
> +
> +                       if (!p->mem_priv)
> +                               continue;
> +                       if (p->dbuf_mapped) {
> +                               call_memop(q, unmap_dmabuf, p->mem_priv);
> +                               p->dbuf_mapped = 0;
> +                       }
> +               }
> +       }
>  }
>
>  /**
> --
> 1.7.7.3
>
>
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