Max,
Thanks for your patch.
On 6/20/24 10:45 PM, Max Staudt wrote:
> imgu_vb2_stop_streaming() did not order shutdown items in the inverse
> order and count of what imgu_vb2_start_streaming() does. Consequently,
> v6.7's new WARN_ON in call_s_stream() started screaming because it was
> called multiple times on the entire pipe, yet it should only be called
> when the pipe is interrupted by any first node being taken offline.
>
> This reorders streamoff to be the inverse of streamon, and uses
> analogous conditions to decide when and how often to call additional
> teardown functions.
>
> v4l2_subdev_call(s_stream, 0) remains outside the streaming_lock,
> analogously to imgu_vb2_start_streaming().
>
> Signed-off-by: Max Staudt <mstaudt@xxxxxxxxxxxx>
> ---
> drivers/staging/media/ipu3/ipu3-v4l2.c | 36 +++++++++++++++++++++-----
> 1 file changed, 29 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/staging/media/ipu3/ipu3-v4l2.c b/drivers/staging/media/ipu3/ipu3-v4l2.c
> index 3ff390b04e1a..e7aee7e3db5b 100644
> --- a/drivers/staging/media/ipu3/ipu3-v4l2.c
> +++ b/drivers/staging/media/ipu3/ipu3-v4l2.c
> @@ -535,29 +535,51 @@ static void imgu_vb2_stop_streaming(struct vb2_queue *vq)
> container_of(vq, struct imgu_video_device, vbq);
> int r;
> unsigned int pipe;
> + bool stop_streaming = false;
>
> + /* Verify that the node had been setup with imgu_v4l2_node_setup() */
> WARN_ON(!node->enabled);
>
> pipe = node->pipe;
> dev_dbg(dev, "Try to stream off node [%u][%u]", pipe, node->id);
> - imgu_pipe = &imgu->imgu_pipe[pipe];
> - r = v4l2_subdev_call(&imgu_pipe->imgu_sd.subdev, video, s_stream, 0);
> - if (r)
> - dev_err(&imgu->pci_dev->dev,
> - "failed to stop subdev streaming\n");
I guess the subdev streams API can help us on this, but current fix
looks fine for me.
>
> + /*
> + * When the first node of a streaming setup is stopped, the entire
> + * pipeline needs to stop before individual nodes are disabled.
> + * Perform the inverse of the initial setup.
> + *
> + * Part 1 - s_stream on the entire pipeline
stream on or off? it is a little confusing.
> + */
> mutex_lock(&imgu->streaming_lock);
> - /* Was this the first node with streaming disabled? */
> if (imgu->streaming) {
> /* Yes, really stop streaming now */
> dev_dbg(dev, "IMGU streaming is ready to stop");
> r = imgu_s_stream(imgu, false);
> if (!r)
> imgu->streaming = false;
> + stop_streaming = true;
> }
> -
> mutex_unlock(&imgu->streaming_lock);
>
> + /* Part 2 - s_stream on subdevs
> + *
> + * If we call s_stream multiple times, Linux v6.7's call_s_stream()
> + * WARNs and aborts. Thus, disable all pipes at once, and only once.
> + */
> + if (stop_streaming) {
> + for_each_set_bit(pipe, imgu->css.enabled_pipes,
> + IMGU_MAX_PIPE_NUM) {
> + imgu_pipe = &imgu->imgu_pipe[pipe];
> +
> + r = v4l2_subdev_call(&imgu_pipe->imgu_sd.subdev,
> + video, s_stream, 0);
> + if (r)
> + dev_err(&imgu->pci_dev->dev,
> + "failed to stop subdev streaming\n");
> + }
Is it possible to move this loop into 'if (imgu->streaming)' above?
> + }
> +
> + /* Part 3 - individual node teardown */
> video_device_pipeline_stop(&node->vdev);
> imgu_return_all_buffers(imgu, node, VB2_BUF_STATE_ERROR);
> }
>
--
Best regards,
Bingbu Cao
