linux-kernel - Re: [PATCH v4 3/5] media: uvcvideo: Split uvc_stop

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Message-ID: <CANiDSCvAtKJdwLONx1crMOB5So8qgcSheEwYnxBggN3y11LkPw@mail.gmail.com>
Date: Mon, 30 Jun 2025 15:26:20 +0200
From: Ricardo Ribalda <ribalda@...omium.org>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: Hans de Goede <hansg@...nel.org>, Hans Verkuil <hverkuil@...all.nl>, 
	Hans de Goede <hdegoede@...hat.com>, Mauro Carvalho Chehab <mchehab@...nel.org>, linux-media@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/5] media: uvcvideo: Split uvc_stop_streaming()

On Mon, 30 Jun 2025 at 15:25, Laurent Pinchart
<laurent.pinchart@...asonboard.com> wrote:
>
> On Mon, Jun 30, 2025 at 03:12:38PM +0200, Hans de Goede wrote:
> > On 30-Jun-25 3:10 PM, Laurent Pinchart wrote:
> > > On Mon, Jun 30, 2025 at 02:59:05PM +0200, Hans de Goede wrote:
> > >> 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@...nel.org>
> > >>>> Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
> > >>>> ---
> > >>>>  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 ?
> > >
> > > As far as I understand, some jobs in the media CI use the next branch,
> > > for instance the bisect job that tries to compile every commit uses the
> > > next branch as a base. We therefore need to keep the next branch
> > > up-to-date, mirroring upstream.
> >
> > Ok, so we have the next branch mirroring upstream and then we
> > use for-next to merge new patches as I've just done ?
>
> Sounds good.

BTW the auto-mirroring from media-committers has not been enabled. Do
you want it?

>
> --
> Regards,
>
> Laurent Pinchart



-- 
Ricardo Ribalda