Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752355AbaAQOgZ (ORCPT ); Fri, 17 Jan 2014 09:36:25 -0500 Received: from mx0.aculab.com ([213.249.233.131]:44380 "HELO mx0.aculab.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751965AbaAQOgX (ORCPT ); Fri, 17 Jan 2014 09:36:23 -0500 From: David Laight To: "'walt'" , Sarah Sharp CC: Alan Stern , Greg Kroah-Hartman , Linux Kernel , "stable@vger.kernel.org" , "linux-usb@vger.kernel.org" , "linux-scsi@vger.kernel.org" Subject: RE: [PATCH 3.12 033/118] usb: xhci: Link TRB must not occur within a USB payload burst [NEW HARDWARE] Thread-Topic: [PATCH 3.12 033/118] usb: xhci: Link TRB must not occur within a USB payload burst [NEW HARDWARE] Thread-Index: AQHPELhlWPjDYPI+s0G+DC1zL1oFlJqEeIcAgABE3oCABEGkcA== Date: Fri, 17 Jan 2014 14:34:07 +0000 Message-ID: <063D6719AE5E284EB5DD2968C1650D6D45EDA3@AcuExch.aculab.com> References: <20140109235045.GA17660@xanatos> <52D4791B.3030309@gmail.com> <20140114172056.GB12126@xanatos> <52D5ABBD.7090202@gmail.com> In-Reply-To: <52D5ABBD.7090202@gmail.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.202.99.200] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 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 base64 to 8bit by mail.home.local id s0HEadHH025124 From: walt > Oy, Sarah! ;) I put the ASMedia adapter in my older amd64 machine, and, well, > the stupid thing Just Works(TM) with kernel 3.12.7! (Yes, with the same disk > docking station, too.) > > I can't believe the adapter works perfectly in a different computer. Have you > seen this kind of thing before? Could be a horrid timing race between the cpu and xchi controller. If the cpu manages to write a NOP or LINK TRB for a following transfer before the controller polls the next entry (after raising the IRQ) then the controller might process the LINK and then get confused when it can't process the linked-to TRB. This might not sound likely, but PCIe has significant latency. > At the moment I have two machines using your xhci driver and both work perfectly, > so I thank you again :) > > I'm not sure where to go with this next. I could put the adapter back in the > other machine again if you have more patches to test. Can you try the patch I posted that stops the ownership on LINK TRBs being changed before that on the linked-to TRB? I got a private mail from someone indicating that my earlier 'minimal' patch helped an ASMedia controller talking to the asx189_178a ethernet hardware. David ????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?