Re: [PATCH 4/7] usb: gadget: uvc: only schedule stream in streaming state

[paul.elder@ideasonboard.com]

Hi Michael,

On Thu, Sep 30, 2021 at 12:27:14PM +0200, Michael Grzeschik wrote:
> This patch ensures that the video pump thread will only be scheduled if
> the uvc is really in streaming state. This way the worker will not have
> to run on an empty queue.
> 
> Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>

Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

> ---
>  drivers/usb/gadget/function/uvc_v4l2.c  | 3 ++-
>  drivers/usb/gadget/function/uvc_video.c | 4 +++-
>  2 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
> index 4ca89eab61590..67922b1355e69 100644
> --- a/drivers/usb/gadget/function/uvc_v4l2.c
> +++ b/drivers/usb/gadget/function/uvc_v4l2.c
> @@ -169,7 +169,8 @@ uvc_v4l2_qbuf(struct file *file, void *fh, struct v4l2_buffer *b)
>  	if (ret < 0)
>  		return ret;
>  
> -	schedule_work(&video->pump);
> +	if (uvc->state == UVC_STATE_STREAMING)
> +		schedule_work(&video->pump);
>  
>  	return ret;
>  }
> diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
> index cdfd3726a86ae..ccee35177411d 100644
> --- a/drivers/usb/gadget/function/uvc_video.c
> +++ b/drivers/usb/gadget/function/uvc_video.c
> @@ -215,6 +215,7 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
>  	struct uvc_request *ureq = req->context;
>  	struct uvc_video *video = ureq->video;
>  	struct uvc_video_queue *queue = &video->queue;
> +	struct uvc_device *uvc = video->uvc;
>  	unsigned long flags;
>  
>  	switch (req->status) {
> @@ -237,7 +238,8 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
>  	list_add_tail(&req->list, &video->req_free);
>  	spin_unlock_irqrestore(&video->req_lock, flags);
>  
> -	schedule_work(&video->pump);
> +	if (uvc->state == UVC_STATE_STREAMING)
> +		schedule_work(&video->pump);
>  }
>  
>  static int
> -- 
> 2.30.2
>