From: Michael Grzeschik m.grzeschik@pengutronix.de
[ Upstream commit 9b91a65230784a9ef644b8bdbb82a79ba4ae9456 ]
This patch is changing the simple workqueue in the gadget driver to be allocated as async_wq with a higher priority. The pump worker, that is filling the usb requests, will have a higher priority and will not be scheduled away so often while the video stream is handled. This will lead to fewer streaming underruns.
Signed-off-by: Michael Grzeschik m.grzeschik@pengutronix.de Link: https://lore.kernel.org/r/20220907215818.2670097-1-m.grzeschik@pengutronix.d... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/gadget/function/f_uvc.c | 4 ++++ drivers/usb/gadget/function/uvc.h | 1 + drivers/usb/gadget/function/uvc_v4l2.c | 2 +- drivers/usb/gadget/function/uvc_video.c | 9 +++++++-- 4 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c index 86bb0098fb66..7ec223849d94 100644 --- a/drivers/usb/gadget/function/f_uvc.c +++ b/drivers/usb/gadget/function/f_uvc.c @@ -897,10 +897,14 @@ static void uvc_function_unbind(struct usb_configuration *c, { struct usb_composite_dev *cdev = c->cdev; struct uvc_device *uvc = to_uvc(f); + struct uvc_video *video = &uvc->video; long wait_ret = 1;
uvcg_info(f, "%s()\n", __func__);
+ if (video->async_wq) + destroy_workqueue(video->async_wq); + /* * If we know we're connected via v4l2, then there should be a cleanup * of the device from userspace either via UVC_EVENT_DISCONNECT or diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h index 58e383afdd44..1a31e6c6a5ff 100644 --- a/drivers/usb/gadget/function/uvc.h +++ b/drivers/usb/gadget/function/uvc.h @@ -88,6 +88,7 @@ struct uvc_video { struct usb_ep *ep;
struct work_struct pump; + struct workqueue_struct *async_wq;
/* Frame parameters */ u8 bpp; diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c index fd8f73bb726d..fddc392b8ab9 100644 --- a/drivers/usb/gadget/function/uvc_v4l2.c +++ b/drivers/usb/gadget/function/uvc_v4l2.c @@ -170,7 +170,7 @@ uvc_v4l2_qbuf(struct file *file, void *fh, struct v4l2_buffer *b) return ret;
if (uvc->state == UVC_STATE_STREAMING) - schedule_work(&video->pump); + queue_work(video->async_wq, &video->pump);
return ret; } diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c index c00ce0e91f5d..bb037fcc90e6 100644 --- a/drivers/usb/gadget/function/uvc_video.c +++ b/drivers/usb/gadget/function/uvc_video.c @@ -277,7 +277,7 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req) spin_unlock_irqrestore(&video->req_lock, flags);
if (uvc->state == UVC_STATE_STREAMING) - schedule_work(&video->pump); + queue_work(video->async_wq, &video->pump); }
static int @@ -485,7 +485,7 @@ int uvcg_video_enable(struct uvc_video *video, int enable)
video->req_int_count = 0;
- schedule_work(&video->pump); + queue_work(video->async_wq, &video->pump);
return ret; } @@ -499,6 +499,11 @@ int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc) spin_lock_init(&video->req_lock); INIT_WORK(&video->pump, uvcg_video_pump);
+ /* Allocate a work queue for asynchronous video pump handler. */ + video->async_wq = alloc_workqueue("uvcgadget", WQ_UNBOUND | WQ_HIGHPRI, 0); + if (!video->async_wq) + return -EINVAL; + video->uvc = uvc; video->fcc = V4L2_PIX_FMT_YUYV; video->bpp = 16;