@@ -91,6 +91,9 @@ struct uvc_video {
struct work_struct pump;
struct workqueue_struct *async_wq;
+ int enqueued;
+ int dequeued;
+
/* Frame parameters */
u8 bpp;
u32 fcc;
@@ -106,7 +109,7 @@ struct uvc_video {
unsigned int req_size;
struct list_head ureqs; /* all uvc_requests allocated by uvc_video */
- /* USB requests that the video pump thread can encode into */
+ /* USB requests that the video qbuf thread can encode into */
struct list_head req_free;
/*
@@ -269,6 +269,8 @@ static int uvcg_video_ep_queue(struct uvc_video *video, struct usb_request *req)
}
}
+ video->enqueued++;
+
return ret;
}
@@ -380,6 +382,7 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
int ret = 0;
spin_lock_irqsave(&video->req_lock, flags);
+ video->dequeued++;
if (!video->is_enabled) {
/*
* When is_enabled is false, uvcg_video_disable() ensures
@@ -467,6 +470,10 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
* happen.
*/
queue_work(video->async_wq, &video->pump);
+ } else if ((video->enqueued - video->dequeued) > 32) {
+ spin_unlock_irqrestore(&video->req_lock, flags);
+
+ return;
}
/*
* Queue to the endpoint. The actual queueing to ep will
The complete handler will at least be called after 16 requests have completed, but will still handle all finisher requests. Since we have to maintain a costant filling in the isoc queue we ensure this by adding zero length requests. By counting the amount enqueued requests we can ensure that the queue is never underrun and only need to get active if the queue is running critical. This patch is setting 32 as the critical level, which is twice the request amount that is needed to create interrupts. Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> --- v3 -> v4: - v1 -> v3: new patch --- drivers/usb/gadget/function/uvc.h | 5 ++++- drivers/usb/gadget/function/uvc_video.c | 7 +++++++ 2 files changed, 11 insertions(+), 1 deletion(-)