Hi Jim, On Friday 14 Jul 2017 09:58:11 Jim Lin wrote: > On 2017年07月11日 03:47, Laurent Pinchart wrote: > > On Monday 10 Jul 2017 14:43:49 Jim Lin wrote: > >> Section 9.2.6.4 of USB 2.0/3.x specification describes that > >> "device must be able to return the first data packet to host within > >> 500 ms of receipt of the request. For subsequent data packet, if any, > >> the device must be able to return them within 500 ms". > >> > >> This is to fix incorrect timeout and change it from 300 ms to 500 ms > >> to meet the timing specified by specification for Get Request. > >> > >> Signed-off-by: Jim Lin <jilin@xxxxxxxxxx> > > > > The patch looks good to me, so > > > > Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > > > > but I'm curious, have you noticed issues with some devices in practice ? > > Sometimes this device takes about 360 ms to respond. > > usb 1-2: new high-speed USB device number 16 > usb 1-2: New USB device found, idVendor=045e, idProduct=0772 > usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0 > usb 1-2: Product: Microsoft�® LifeCam Studio(TM) > usb 1-2: Manufacturer: Microsoft > > uvcvideo: Failed to query (GET_DEF) UVC control 2 on unit 4: -110 (exp. 2). > > And it will be working well with correct timeout value. Thank you for the information. I've applied the patch to my tree and will push it to v4.14. -- Regards, Laurent Pinchart
