Re: [PATCH 1/1 V2] media: usb: uvc: Fix incorrect timeout for Get Request

[Laurent Pinchart]

Hi Jim,

On Friday 14 Jul 2017 09:58:11 Jim Lin wrote:
> On 2017å07æ11æ 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: Microsoftï 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