Hi Bhupesh, Thanks for the patch. On Thursday 28 March 2013 15:11:52 Bhupesh Sharma wrote: > This patch reworks the videobuffer management logic present in the UVC > webcam gadget and ports it to use the "more apt" videobuf2 framework for > video buffer management. > > To support routing video data captured from a real V4L2 video capture > device with a "zero copy" operation on videobuffers (as they pass from > the V4L2 domain to UVC domain via a user-space application), we need to > support USER_PTR IO method at the UVC gadget side. > > So the V4L2 capture device driver can still continue to use MMAP IO > method and now the user-space application can just pass a pointer to the > video buffers being dequeued from the V4L2 device side while queueing > them at the UVC gadget end. This ensures that we have a "zero-copy" > design as the videobuffers pass from the V4L2 capture device to the UVC > gadget. > > Note that there will still be a need to apply UVC specific payload > headers on top of each UVC payload data, which will still require a copy > operation to be performed in the 'encode' routines of the UVC gadget. > > This patch also addresses one issue found out while porting the UVC > gadget to videobuf2 framework: > - In case the usb requests queued by the gadget get completed > with a status of -ESHUTDOWN (disconnected from host), > the queue of videobuf2 should be cancelled to ensure that the > application space daemon is not left in a state waiting for > a vb2 to be successfully absorbed at the USB side. > > Signed-off-by: Bhupesh Sharma <bhupesh.sharma@xxxxxx> Finally, Acked-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> :-) -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
