Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753296AbaAUWHL (ORCPT ); Tue, 21 Jan 2014 17:07:11 -0500 Received: from mail-pd0-f180.google.com ([209.85.192.180]:47461 "EHLO mail-pd0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750862AbaAUWHI (ORCPT ); Tue, 21 Jan 2014 17:07:08 -0500 Message-ID: <52DEEF88.8090709@gmail.com> Date: Tue, 21 Jan 2014 14:07:04 -0800 From: walt User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.1 MIME-Version: 1.0 To: David Laight , "'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] References: <20140109235045.GA17660@xanatos> <52D4791B.3030309@gmail.com> <20140114172056.GB12126@xanatos> <52D5ABBD.7090202@gmail.com> <063D6719AE5E284EB5DD2968C1650D6D45EDA3@AcuExch.aculab.com> <52DAE2BF.7020208@gmail.com> <063D6719AE5E284EB5DD2968C1650D6D45FF6C@AcuExch.aculab.com> <20140120181442.GA5545@xanatos> <063D6719AE5E284EB5DD2968C1650D6D4609BF@AcuExch.aculab.com> In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D4609BF@AcuExch.aculab.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/21/2014 01:51 AM, David Laight wrote: > From: Sarah Sharp >> On Mon, Jan 20, 2014 at 11:21:14AM +0000, David Laight wrote: > ... >>> A guess... >>> >>> In queue_bulk_sg_tx() try calling xhci_v1_0_td_remainder() instead >>> of xhci_td_remainder(). >> >> Why? Walt has a 0.96 xHCI host controller, and the format for how to >> calculate the TD remainder changed between the 0.96 and the 1.0 spec. >> That's why we have xhci_v1_0_td_remainder() and xhci_td_remainder(). > > I just wonder how many of those differences are just differences in the > specification, rather than differences in the hardware implementation. > In some cases it might be that the old hardware just ignored the value. > > I know that the xhci hardware on my ivy bridge cpu does look at that > value (at least checking for zero), since things failed in subtle ways > when I got it wrong. > > In this case it was just something easy to change that might be worth > trying. I didn't necessarily expect it to make a positive difference. David, I tried the one-liner below, which changed nothing AFAICS, but then I'm not sure it's the change you intended: --- xhci-ring.c.orig 2014-01-21 13:28:36.396278813 -0800 +++ xhci-ring.c 2014-01-21 13:35:11.410312814 -0800 @@ -3335,7 +3335,7 @@ } /* Set the TRB length, TD size, and interrupter fields. */ - if (xhci->hci_version < 0x100) { + if (xhci->hci_version > 0x100) { remainder = xhci_td_remainder( urb->transfer_buffer_length - running_total); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/