On Tue, Oct 05, 2021 at 02:06:22PM +0300, Felipe Balbi wrote: > > Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> writes: > > > On Tue, Oct 05, 2021 at 02:53:48AM +0300, Laurent Pinchart wrote: > >> Hi Michael, > >> > >> Thank you for resending this. > >> > >> On Sun, Oct 03, 2021 at 10:13:55PM +0200, Michael Grzeschik wrote: > >> > From: Thomas Haemmerle <thomas.haemmerle@xxxxxxxxxxxxxx> > >> > > >> > Currently, the UVC function is activated when open on the corresponding > >> > v4l2 device is called. > >> > On another open the activation of the function fails since the > >> > deactivation counter in `usb_function_activate` equals 0. However the > >> > error is not returned to userspace since the open of the v4l2 device is > >> > successful. > >> > > >> > On a close the function is deactivated (since deactivation counter still > >> > equals 0) and the video is disabled in `uvc_v4l2_release`, although the > >> > UVC application potentially is streaming. > >> > > >> > Move activation of UVC function to subscription on UVC_EVENT_SETUP > >> > because there we can guarantee for a userspace application utilizing > >> > UVC. > >> > Block subscription on UVC_EVENT_SETUP while another application already > >> > is subscribed to it, indicated by `bool func_connected` in > >> > `struct uvc_device`. > >> > Extend the `struct uvc_file_handle` with member `bool is_uvc_app_handle` > >> > to tag it as the handle used by the userspace UVC application. > >> > >> Reflowing the paragraph would be nice (this could be done when applying > >> the patch, or not at all). > >> > >> > With this a process is able to check capabilities of the v4l2 device > >> > without deactivating the function for the actual UVC application. > >> > > >> > Reviewed-By: Michael Tretter <m.tretter@xxxxxxxxxxxxxx> > >> > Signed-off-by: Thomas Haemmerle <thomas.haemmerle@xxxxxxxxxxxxxx> > >> > Signed-off-by: Michael Tretter <m.tretter@xxxxxxxxxxxxxx> > >> > Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx> > >> > >> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > >> > >> Felipe, please let me know if you want me to take this in my tree and > >> issue a pull request, otherwise I'll assume you'll pick it up. > > > > I'll pick it up now, thanks. > > I guess it's too late for an Ack. FWIW: > > Acked-by: Felipe Balbi <balbi@xxxxxxxxxx> Nope, not too late, just added, thanks! greg k-h
