Re: [PATCH v4 3/5] media: uvcvideo: Split uvc_stop_streaming()

[Hans de Goede]

Hi all,

On 17-Jun-25 11:27 AM, Hans Verkuil wrote:
> On 16/06/2025 17:24, Ricardo Ribalda wrote:
>> uvc_stop_streaming() is used for meta and video nodes. Split the function
>> in two to avoid confusion.
>>
>> Use this opportunity to rename uvc_start_streaming() to
>> uvc_start_streaming_video(), as it is only called by the video nodes.
>>
>> Reviewed-by: Hans de Goede <hansg@xxxxxxxxxx>
>> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
>> ---
>>  drivers/media/usb/uvc/uvc_queue.c | 22 +++++++++++++++-------
>>  1 file changed, 15 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
>> index 8f9737ac729546683ca48f5e71ce3dfacbae2926..3f357c2d48cfd258c26f0342007d1d12f1e01007 100644
>> --- a/drivers/media/usb/uvc/uvc_queue.c
>> +++ b/drivers/media/usb/uvc/uvc_queue.c
>> @@ -167,7 +167,7 @@ static void uvc_buffer_finish(struct vb2_buffer *vb)
>>  		uvc_video_clock_update(stream, vbuf, buf);
>>  }
>>  
>> -static int uvc_start_streaming(struct vb2_queue *vq, unsigned int count)
>> +static int uvc_start_streaming_video(struct vb2_queue *vq, unsigned int count)
>>  {
>>  	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
>>  	struct uvc_streaming *stream = uvc_queue_to_stream(queue);
>> @@ -186,14 +186,22 @@ static int uvc_start_streaming(struct vb2_queue *vq, unsigned int count)
>>  	return ret;
>>  }
>>  
>> -static void uvc_stop_streaming(struct vb2_queue *vq)
>> +static void uvc_stop_streaming_video(struct vb2_queue *vq)
>>  {
>>  	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
>>  
>>  	lockdep_assert_irqs_enabled();
>>  
>> -	if (vq->type != V4L2_BUF_TYPE_META_CAPTURE)
>> -		uvc_video_stop_streaming(uvc_queue_to_stream(queue));
>> +	uvc_video_stop_streaming(uvc_queue_to_stream(queue));
>> +
>> +	uvc_queue_return_buffers(queue, UVC_BUF_STATE_ERROR);
>> +}
>> +
>> +static void uvc_stop_streaming_meta(struct vb2_queue *vq)
>> +{
>> +	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
>> +
>> +	lockdep_assert_irqs_enabled();
>>  
>>  	uvc_queue_return_buffers(queue, UVC_BUF_STATE_ERROR);
>>  }
>> @@ -203,15 +211,15 @@ static const struct vb2_ops uvc_queue_qops = {
>>  	.buf_prepare = uvc_buffer_prepare,
>>  	.buf_queue = uvc_buffer_queue,
>>  	.buf_finish = uvc_buffer_finish,
>> -	.start_streaming = uvc_start_streaming,
>> -	.stop_streaming = uvc_stop_streaming,
>> +	.start_streaming = uvc_start_streaming_video,
>> +	.stop_streaming = uvc_stop_streaming_video,
>>  };
>>  
>>  static const struct vb2_ops uvc_meta_queue_qops = {
>>  	.queue_setup = uvc_queue_setup,
>>  	.buf_prepare = uvc_buffer_prepare,
>>  	.buf_queue = uvc_buffer_queue,
>> -	.stop_streaming = uvc_stop_streaming,
>> +	.stop_streaming = uvc_stop_streaming_meta,
>>  };
> 
> I think there should be a comment stating that the metadata stream
> expects that video is streaming, it does not start streaming by itself.
> 
> Something like:
> 
> 	/*
> 	 * .start_streaming is not provided here. Metadata relies on
> 	 * video streaming being active. If video isn't streaming, then
> 	 * no metadata will arrive either.
> 	 */
> 
> It's unexpected that there is no start_streaming for metadata, so a
> comment wouldn't hurt.

I've added this comment while merging this series and I've now pushed
the entire series to uvc.git/for-next .

BTW it seems that both uvc.git/next and uvc.git/for-next are in
use now?  With uvc.git/next seemingly following media-commiters/next ?

I thought we had agreed to only use uvc.git/for-next ?

Regards,

Hans