From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752776AbdGNHeV (ORCPT ); Fri, 14 Jul 2017 03:34:21 -0400 Received: from galahad.ideasonboard.com ([185.26.127.97]:40260 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751380AbdGNHeU (ORCPT ); Fri, 14 Jul 2017 03:34:20 -0400 From: Laurent Pinchart To: Jim Lin 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 Message-ID: <1696193.EoNaQecsU9@avalon> User-Agent: KMail/4.14.10 (Linux/4.9.34-gentoo; KDE/4.14.32; x86_64; ; ) In-Reply-To: <3a7d73bb-45f8-4803-ee9b-8bf2ead84017@nvidia.com> References: <1499669029-3412-1-git-send-email-jilin@nvidia.com> <3026364.oSOK2ZPSm0@avalon> <3a7d73bb-45f8-4803-ee9b-8bf2ead84017@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id v6E7YOrb022485 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 > > > > The patch looks good to me, so > > > > Reviewed-by: Laurent Pinchart > > > > 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