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From: Jim Lin <jilin@nvidia.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.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 10:11:53 +0800	[thread overview]
Message-ID: <75068995-ce49-dbac-76cb-f4fe911cb597@nvidia.com> (raw)
In-Reply-To: <3026364.oSOK2ZPSm0@avalon>

On 2017年07月11日 03:47, Laurent Pinchart wrote:
> Hi Jim,
>
> Thank you for the patch.
>
> 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@nvidia.com>
>
> The patch looks good to me, so
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.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.

--nvpublic

  reply	other threads:[~2017-07-14  2:11 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-10  6:43 [PATCH 1/1 V2] media: usb: uvc: Fix incorrect timeout for Get Request Jim Lin
2017-07-10 19:47 ` Laurent Pinchart
2017-07-14  2:11   ` Jim Lin [this message]
     [not found]   ` <3a7d73bb-45f8-4803-ee9b-8bf2ead84017@nvidia.com>
2017-07-14  7:34     ` Laurent Pinchart

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