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        Fri, 14 Jul 2017 03:34:20 -0400
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Jim Lin <jilin@nvidia.com>
Cc: mchehab@kernel.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org
Subject: Re: [PATCH 1/1 V2] media: usb: uvc: Fix incorrect timeout for Get Request
Date: Fri, 14 Jul 2017 10:34:23 +0300
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Hi Jim,

On Friday 14 Jul 2017 09:58:11 Jim Lin wrote:
> On 2017=E5=B9=B407=E6=9C=8811=E6=97=A5 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 withi=
n
> >> 500 ms of receipt of the request. For subsequent data packet, if a=
ny,
> >> the device must be able to return them within 500 ms".
> >>=20
> >> 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.
> >>=20
> >> Signed-off-by: Jim Lin <jilin@nvidia.com>
> >=20
> > The patch looks good to me, so
> >=20
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> >=20
> > but I'm curious, have you noticed issues with some devices in pract=
ice ?
>=20
> Sometimes this device takes about 360 ms to respond.
>=20
> usb 1-2: new high-speed USB device number 16
> usb 1-2: New USB device found, idVendor=3D045e, idProduct=3D0772
> usb 1-2: New USB device strings: Mfr=3D1, Product=3D2, SerialNumber=3D=
0
> usb 1-2: Product: Microsoft=EF=BF=BD=C2=AE LifeCam Studio(TM)
> usb 1-2: Manufacturer: Microsoft
>=20
> uvcvideo: Failed to query (GET_DEF) UVC control 2 on unit 4: -110 (ex=
p. 2).
>=20
> 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.

--=20
Regards,

Laurent Pinchart