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 B89E3C433E0 for ; Wed, 20 May 2020 18:59:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88F5D207D3 for ; Wed, 20 May 2020 18:59:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="d/E1rcY7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726566AbgETS7X (ORCPT ); Wed, 20 May 2020 14:59:23 -0400 Received: from fllv0015.ext.ti.com ([198.47.19.141]:50924 "EHLO fllv0015.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726548AbgETS7X (ORCPT ); Wed, 20 May 2020 14:59:23 -0400 Received: from fllv0034.itg.ti.com ([10.64.40.246]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 04KIxLbh044879; Wed, 20 May 2020 13:59:21 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1590001161; bh=173hVH3ooEaNTJDeg0ZFoaFCIdVe9uzwY5Mr6pYJb1s=; h=Date:From:To:CC:Subject:References:In-Reply-To; b=d/E1rcY7JEvcCvoTv6m5JKLAbet4XTBfV5IZ8FavaiYS7PmSrhiKtNe5isIktHiwQ QOgnFQlblgpV2K33Nhxr3I/Xqp07fjTpz9dVZcGdKazJYjVMi7queMJ2bSDUb4iceX ZMHnEpgK0/p5jjJ5u+QBtImssNZdjEzz7crPAQR0= Received: from DFLE102.ent.ti.com (dfle102.ent.ti.com [10.64.6.23]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 04KIxLrs116404 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 20 May 2020 13:59:21 -0500 Received: from DFLE105.ent.ti.com (10.64.6.26) by DFLE102.ent.ti.com (10.64.6.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1979.3; Wed, 20 May 2020 13:59:21 -0500 Received: from lelv0327.itg.ti.com (10.180.67.183) by DFLE105.ent.ti.com (10.64.6.26) 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; Wed, 20 May 2020 13:59:21 -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 04KIxLd2010450; Wed, 20 May 2020 13:59:21 -0500 Date: Wed, 20 May 2020 13:59:21 -0500 From: Bin Liu To: Alan Stern CC: Subject: Re: [PATCH] usb: musb: return -ESHUTDOWN in urb when three-strikes error happened Message-ID: <20200520185921.GE15845@iaqt7> Mail-Followup-To: Bin Liu , Alan Stern , linux-usb@vger.kernel.org References: <20200514153731.GC11463@iaqt7> <20200514162604.GA9571@rowland.harvard.edu> <20200514170023.GD11463@iaqt7> <20200514185549.GA22428@rowland.harvard.edu> <20200519171255.GE11463@iaqt7> <20200519200158.GA1339@rowland.harvard.edu> <20200520143112.GB15845@iaqt7> <20200520164055.GB11084@rowland.harvard.edu> <20200520180550.GD15845@iaqt7> <20200520182536.GB15590@rowland.harvard.edu> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20200520182536.GB15590@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 Wed, May 20, 2020 at 02:25:36PM -0400, Alan Stern wrote: > On Wed, May 20, 2020 at 01:05:50PM -0500, Bin Liu wrote: > > On Wed, May 20, 2020 at 12:40:55PM -0400, Alan Stern wrote: > > > > > Then do you think we should change the API? > > > > > > > > > > Right now it's a little too complicated. There's no real reason for > > > > > EPROTO, EILSEQ, and ETIME to be different codes. And now you seem to be > > > > > suggesting that we should fold them all into ESHUTDOWN. > > > > > > > > I haven't studied all the USB error code enough to suggest this. I am > > > > only changing to ESHUTDOWN in musb driver because I know this 3-strikes > > > > error should only be caused by USB device disabled, which is the > > > > definition of ESHUTDOWN in error-code.rst. > > > > > > You should spend a little time studying the error-codes document. > > > EPROTO, EILSEQ, and ETIME describe different kinds of errors that all > > > fall into the 3-strikes category. > > > > But not all device drivers, except the 3 I found, treat EPROTO as fatal, > > and I cannot fix it in all the device drivers. The only thing I can do > > at this moment is changing the MUSB HCD driver to return ESHUTDOWN which > > still follows the document, kind of. > > Think long-term. Yes, for now you're focused on changing the MUSB HCD. > But what should happen in the future? > > At some point we all need to stop reacting and start making some > deliberate plans. This issue is bigger than one patch or one driver. Yes, the issue big, not all device drivers treat the urb error status properly. As the case #3 I mentioned earlier, even MUSB HCD returns ESHUTDOWN, the interrupt storm still happens. Unfortunately before I located the offending device driver, the remote setup is gone... I agree with you, we probably should simply the number of the error code based on the real usecases and the handlings in device drivers. -Bin.