[PATCH] uvcvideo: Implement videobuf2 .wait_prepare and .wait_finish operations

[PATCH] uvcvideo: Implement videobuf2 .wait_prepare and .wait_finish operations

[Laurent Pinchart]

Those optional operations are used to release and reacquire the queue
lock when videobuf2 needs to perform operations that sleep for a long
time, such as waiting for a buffer to be complete. Implement them to
avoid blocking qbuf or streamoff calls when a dqbuf is in progress.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 drivers/media/usb/uvc/uvc_queue.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
index 778addc..6c233a5 100644
--- a/drivers/media/usb/uvc/uvc_queue.c
+++ b/drivers/media/usb/uvc/uvc_queue.c
@@ -115,11 +115,27 @@ static int uvc_buffer_finish(struct vb2_buffer *vb)
 	return 0;
 }
 
+static void uvc_wait_prepare(struct vb2_queue *vq)
+{
+	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
+
+	mutex_unlock(&queue->mutex);
+}
+
+static void uvc_wait_finish(struct vb2_queue *vq)
+{
+	struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
+
+	mutex_lock(&queue->mutex);
+}
+
 static struct vb2_ops uvc_queue_qops = {
 	.queue_setup = uvc_queue_setup,
 	.buf_prepare = uvc_buffer_prepare,
 	.buf_queue = uvc_buffer_queue,
 	.buf_finish = uvc_buffer_finish,
+	.wait_prepare = uvc_wait_prepare,
+	.wait_finish = uvc_wait_finish,
 };
 
 int uvc_queue_init(struct uvc_video_queue *queue, enum v4l2_buf_type type,
-- 
Regards,

Laurent Pinchart

Re: [PATCH] uvcvideo: Implement videobuf2 .wait_prepare and .wait_finish operations

[Laurent Pinchart]

Hi Sean,

On Monday 04 February 2013 12:36:47 Sean V Kelley wrote:
> On Mon, Jan 21, 2013 at 2:51 AM, Laurent Pinchart wrote:
> > Those optional operations are used to release and reacquire the queue
> > lock when videobuf2 needs to perform operations that sleep for a long
> > time, such as waiting for a buffer to be complete. Implement them to
> > avoid blocking qbuf or streamoff calls when a dqbuf is in progress.
> 
> Speaking of UVC, are there plans to look into supporting UVC 1.5
> specification?  Are you aware of any development in that area for new
> controls?

There's work in progress to implement UVC 1.5 but I'm not sure how much 
details I can share. I should get a progress report in two weeks at the ELC in 
San Francisco, will you happen to be there by any chance ?

You're the third Intel developer who contacts me about UVC in the last 3 days, 
I assume that's not a coincidence. If you ever need consulting services on the 
uvcvideo driver (or just if you think collaboration would be helpful) please 
feel free to contact me.

-- 
Regards,

Laurent Pinchart