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 X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66088C433DF for ; Tue, 19 May 2020 17:12:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 340E420709 for ; Tue, 19 May 2020 17:12:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="Lc/O6OTT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729219AbgESRM5 (ORCPT ); Tue, 19 May 2020 13:12:57 -0400 Received: from lelv0142.ext.ti.com ([198.47.23.249]:33832 "EHLO lelv0142.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729001AbgESRM5 (ORCPT ); Tue, 19 May 2020 13:12:57 -0400 Received: from fllv0034.itg.ti.com ([10.64.40.246]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id 04JHCtjb046522; Tue, 19 May 2020 12:12:55 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1589908375; bh=KMAbIYvMyQmaEGU7emJfKnr+OEPZ54ytAw8zdAt34oE=; h=Date:From:To:CC:Subject:References:In-Reply-To; b=Lc/O6OTT6OiQhhXczZY9PhFo+i/8hFkPP+ebN6q2CXHIdli/2aucUPnZjEpImCvoj l1BTSXvXyd1562fscfvTcnjHKO6hbJnBJBKtsrSQkRMLMJ1OaTlBExEhf9wTB+SGsI htvJk/gNxym5w82534Bq5BImgpX/Em3WqpmSh3iE= Received: from DLEE100.ent.ti.com (dlee100.ent.ti.com [157.170.170.30]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 04JHCt5o043539 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 19 May 2020 12:12:55 -0500 Received: from DLEE115.ent.ti.com (157.170.170.26) by DLEE100.ent.ti.com (157.170.170.30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Tue, 19 May 2020 12:12:55 -0500 Received: from lelv0327.itg.ti.com (10.180.67.183) by DLEE115.ent.ti.com (157.170.170.26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3 via Frontend Transport; Tue, 19 May 2020 12:12:55 -0500 Received: from localhost (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0327.itg.ti.com (8.15.2/8.15.2) with ESMTP id 04JHCt4l052467; Tue, 19 May 2020 12:12:55 -0500 Date: Tue, 19 May 2020 12:12:55 -0500 From: Bin Liu To: Alan Stern CC: Subject: Re: [PATCH] usb: musb: return -ESHUTDOWN in urb when three-strikes error happened Message-ID: <20200519171255.GE11463@iaqt7> Mail-Followup-To: Bin Liu , Alan Stern , linux-usb@vger.kernel.org References: <20200513213620.21541-1-b-liu@ti.com> <20200514013205.GA10515@rowland.harvard.edu> <20200514142803.GA11463@iaqt7> <20200514144053.GC12181@rowland.harvard.edu> <20200514150259.GB11463@iaqt7> <20200514153731.GC11463@iaqt7> <20200514162604.GA9571@rowland.harvard.edu> <20200514170023.GD11463@iaqt7> <20200514185549.GA22428@rowland.harvard.edu> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20200514185549.GA22428@rowland.harvard.edu> User-Agent: Mutt/1.9.4 (2018-02-28) X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Thu, May 14, 2020 at 02:55:49PM -0400, Alan Stern wrote: > On Thu, May 14, 2020 at 12:00:23PM -0500, Bin Liu wrote: > > > > Still, it's worth pointing out that this change abuses the API (perhaps > > > mentioning it in a comment). And it still would be preferable to fix > > > > Okay, I will add those notes in comment in v2. > > > > > the drivers in question, impractical though that may be. (I have a hard > > > time believing there are really 500 of them getting this wrong...) > > > > I am not sure about it either, but yeah it is not practical to fix the > > issue in device drivers. So far I have seen 3 reports of this issue: > > > > 1. with FTDI usb-serial adapter, the issue is in the usb serial generic > > driver; > > It shouldn't be hard to fix this. We don't even need a delayed retry; > the driver can simply treat -EPROTO as an unrecoverable error, just like > -ESHUTDOWN. This is just an example showing that it is not practical to fix the problem in device drivers. BTY, I just briefly searched the drivers/ folder, there are only three drivers handle -EPROTO specifically in rx callback and bail out. So seems most drivers do not care about -EPROTO. -Bin.