On 14/09/16 00:16, Laurent Pinchart wrote:
> From: Kieran Bingham <kieran+rene...@bingham.xyz>
>
> The frame-end function releases and completes the buffers on the input
> and output entities of the pipe before marking the pipe->state as
> 'STOPPED'. This introduces a race whereby with the pipe->state still
> 'RUNNING', a QBUF handler can commence processing a frame before the
> frame_end function has completed.
>
> In the event that this happens, a frame queued by QBUF hangs due to the
> incorrect pipe->state setting which prevents vsp1_pipeline_run from
> issuing a CMD_STRCMD.
>
> By locking the entire function we prevent this from occurring, but we
> also change the locking state of the buffer release code. This has been
> analysed visually as acceptable, but it must be considered that this now
> causes the video->irqlock to be taken under the pipe->irqlock context.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
This patch is of course perfectly welcome to my SoB:
Signed-off-by: Kieran Bingham <kieran+rene...@bingham.xyz>
> ---
> drivers/media/platform/vsp1/vsp1_video.c | 9 ++-------
> 1 file changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/media/platform/vsp1/vsp1_video.c
> b/drivers/media/platform/vsp1/vsp1_video.c
> index ed9759e8a6fc..cd7d215ed455 100644
> --- a/drivers/media/platform/vsp1/vsp1_video.c
> +++ b/drivers/media/platform/vsp1/vsp1_video.c
> @@ -234,18 +234,13 @@ static void vsp1_video_frame_end(struct vsp1_pipeline
> *pipe,
> {
> struct vsp1_video *video = rwpf->video;
> struct vsp1_vb2_buffer *buf;
> - unsigned long flags;
>
> buf = vsp1_video_complete_buffer(video);
> if (buf == NULL)
> return;
>
> - spin_lock_irqsave(&pipe->irqlock, flags);
> -
> video->rwpf->mem = buf->mem;
> pipe->buffers_ready |= 1 << video->pipe_index;
> -
> - spin_unlock_irqrestore(&pipe->irqlock, flags);
> }
>
> static void vsp1_video_pipeline_run(struct vsp1_pipeline *pipe)
> @@ -285,6 +280,8 @@ static void vsp1_video_pipeline_frame_end(struct
> vsp1_pipeline *pipe)
> unsigned long flags;
> unsigned int i;
>
> + spin_lock_irqsave(&pipe->irqlock, flags);
> +
> /* Complete buffers on all video nodes. */
> for (i = 0; i < vsp1->info->rpf_count; ++i) {
> if (!pipe->inputs[i])
> @@ -295,8 +292,6 @@ static void vsp1_video_pipeline_frame_end(struct
> vsp1_pipeline *pipe)
>
> vsp1_video_frame_end(pipe, pipe->output);
>
> - spin_lock_irqsave(&pipe->irqlock, flags);
> -
> state = pipe->state;
> pipe->state = VSP1_PIPELINE_STOPPED;
>
>
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