From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6219CC433F5 for ; Fri, 1 Oct 2021 15:22:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4CE9A6115A for ; Fri, 1 Oct 2021 15:22:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354920AbhJAPYT (ORCPT ); Fri, 1 Oct 2021 11:24:19 -0400 Received: from netrider.rowland.org ([192.131.102.5]:42471 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1354734AbhJAPYP (ORCPT ); Fri, 1 Oct 2021 11:24:15 -0400 Received: (qmail 506376 invoked by uid 1000); 1 Oct 2021 11:22:26 -0400 Date: Fri, 1 Oct 2021 11:22:26 -0400 From: Alan Stern To: Hayes Wang Cc: Oliver Neukum , Jason-ch Chen , "matthias.bgg@gmail.com" , "linux-usb@vger.kernel.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-mediatek@lists.infradead.org" , "Project_Global_Chrome_Upstream_Group@mediatek.com" , "hsinyi@google.com" , nic_swsd Subject: Re: [PATCH] r8152: stop submitting rx for -EPROTO Message-ID: <20211001152226.GA505557@rowland.harvard.edu> References: <20210929051812.3107-1-jason-ch.chen@mediatek.com> <4c2ad5e4a9747c59a55d92a8fa0c95df5821188f.camel@mediatek.com> <274ec862-86cf-9d83-7ea7-5786e30ca4a7@suse.com> <20210930151819.GC464826@rowland.harvard.edu> <3694347f29ed431e9f8f2c065b8df0a7@realtek.com> <5f56b21575dd4f64a3b46aac21151667@realtek.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5f56b21575dd4f64a3b46aac21151667@realtek.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 01, 2021 at 03:26:48AM +0000, Hayes Wang wrote: > > Alan Stern > > [...] > > > There has been some discussion about this in the past. > > > > > > In general, -EPROTO is almost always a non-recoverable error. > > > > Excuse me. I am confused about the above description. > > I got -EPROTO before, when I debugged another issue. > > However, the bulk transfer still worked after I resubmitted > > the transfer. I didn't do anything to recover it. That is why > > I do resubmission for -EPROTO. > > I check the Linux driver and the xHCI spec. > The driver gets -EPROTO for bulk transfer, when the host > returns COMP_USB_TRANSACTION_ERROR. > According to the spec of xHCI, USB TRANSACTION ERROR > means the host did not receive a valid response from the > device (Timeout, CRC, Bad PID, unexpected NYET, etc.). That's right. If the device and cable are working properly, this should never happen. Or only extremely rarely (for example, caused by external electromagnetic interference). > It seems to be reasonable why resubmission sometimes works. Did you ever track down the reason why you got the -EPROTO error while debugging that other issue? Can you reproduce it? Alan Stern