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Message-ID: <1696193.EoNaQecsU9@avalon>
Date: Fri, 14 Jul 2017 10:34:23 +0300
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Jim Lin <jilin@...dia.com>
Cc: mchehab@...nel.org, linux-kernel@...r.kernel.org,
linux-media@...r.kernel.org
Subject: Re: [PATCH 1/1 V2] media: usb: uvc: Fix incorrect timeout for Get Request
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@...dia.com>
> >
> > The patch looks good to me, so
> >
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> >
> > 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
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