On Tue, Jun 04, 2013 at 05:08:23PM +0200, Michael Grzeschik wrote: > From: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx> > > The current approach is to keep the device open and request buffers on > REQBUFS. These buffers will not be freed until device close. The device > close on the other hand will disconnect the device from the USB host. > > This way its not possible to change the buffers capabilities while still > being connected. Thus, the device can not stream different buffer types. > > That patch clears the buffers on STREAMOFF. This way it will allways > be needed to alloc new buffers before STREAMON. No, this is wrong. The buffers must still exist after a STREAMON. From the documentation: "I/O returns to the same state as after calling VIDIOC_REQBUFS and can be restarted accordingly." The correct solution is for the userspace to call VIDIOC_REQBUFS with count=0 before calling VIDIOC_S_FMT. Regards, Michael > Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx> > --- > drivers/usb/gadget/uvc_v4l2.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/gadget/uvc_v4l2.c b/drivers/usb/gadget/uvc_v4l2.c > index 4d806b0..9fe2725 100644 > --- a/drivers/usb/gadget/uvc_v4l2.c > +++ b/drivers/usb/gadget/uvc_v4l2.c > @@ -290,7 +290,10 @@ uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg) > if (*type != video->queue.queue.type) > return -EINVAL; > > - return uvc_video_enable(video, 0); > + ret = uvc_video_enable(video, 0); > + uvc_free_buffers(&video->queue); > + > + return ret; > } > > /* Events */ > -- > 1.8.2.rc2 > > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- 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
