Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751715AbXAUWIR (ORCPT ); Sun, 21 Jan 2007 17:08:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751716AbXAUWIR (ORCPT ); Sun, 21 Jan 2007 17:08:17 -0500 Received: from mail.gmx.net ([213.165.64.20]:56038 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751715AbXAUWIQ (ORCPT ); Sun, 21 Jan 2007 17:08:16 -0500 X-Authenticated: #5039886 Date: Sun, 21 Jan 2007 23:08:13 +0100 From: =?iso-8859-1?Q?Bj=F6rn?= Steinbrink To: Robert Hancock Cc: Jeff Garzik , Chr , Alistair John Strachan , linux-kernel@vger.kernel.org, htejun@gmail.com, jens.axboe@oracle.com, lwalton@real.com Subject: Re: SATA exceptions with 2.6.20-rc5 Message-ID: <20070121220811.GA2136@atjola.homenet> Mail-Followup-To: =?iso-8859-1?Q?Bj=F6rn?= Steinbrink , Robert Hancock , Jeff Garzik , Chr , Alistair John Strachan , linux-kernel@vger.kernel.org, htejun@gmail.com, jens.axboe@oracle.com, lwalton@real.com References: <200701191505.33480.s0348365@sms.ed.ac.uk> <45B18160.9020602@shaw.ca> <200701202332.58719.chunkeey@web.de> <45B2C6E1.9000901@shaw.ca> <45B2DF43.8080304@garzik.org> <20070121045437.GA7387@atjola.homenet> <45B30A98.3030206@shaw.ca> <20070121083618.GA2434@atjola.homenet> <20070121184032.GA3220@atjola.homenet> <45B3C5C9.4010007@shaw.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <45B3C5C9.4010007@shaw.ca> User-Agent: Mutt/1.5.13 (2006-08-11) X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1544 Lines: 32 On 2007.01.21 13:58:01 -0600, Robert Hancock wrote: > Bj?rn Steinbrink wrote: > >All kernels were bad using that approach. So back to square 1. :/ > > > >Bj?rn > > > > OK guys, here's a new patch to try against 2.6.20-rc5: > > Right now when switching between ADMA mode and legacy mode (i.e. when > going from doing normal DMA reads/writes to doing a FLUSH CACHE) we just > set the ADMA GO register bit appropriately and continue with no delay. > It looks like in some cases the controller doesn't respond to this > immediately, it takes some nanoseconds for the controller's status > registers to reflect the change that was made. It's possible that if we > were trying to issue commands during this time, the controller might not > react properly. This patch adds some code to wait for the status > register to change to the state we asked for before continuing. I went for the "I feel lucky" route and did just add mmio reads after the mmio writes, posting them. Rationale being that if it is a write posting issue, the debug patch would/could actually hide it AFAICT. It's the "I feel lucky" route, because my whole "knowledge" about mmio and write posting originates from the few things I read up on when you discovered the comment about write posting in the generic ata code. Bj?rn - 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/