From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754101AbZBIAHY (ORCPT ); Sun, 8 Feb 2009 19:07:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753520AbZBIAHK (ORCPT ); Sun, 8 Feb 2009 19:07:10 -0500 Received: from h155.mvista.com ([63.81.120.155]:59193 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752988AbZBIAHJ (ORCPT ); Sun, 8 Feb 2009 19:07:09 -0500 Message-ID: <498F73A5.2070300@ru.mvista.com> Date: Mon, 09 Feb 2009 03:07:01 +0300 From: Sergei Shtylyov User-Agent: Thunderbird 2.0.0.19 (Windows/20081209) MIME-Version: 1.0 To: Hugh Dickins Cc: jgarzik@pobox.com, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, alan@lxorguk.ukuu.org.uk, rjw@sisk.pl Subject: Re: [PATCH] libata-sff: fix 32-bit PIO regression References: <200902082253.07438.sshtylyov@ru.mvista.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. Hugh Dickins wrote: >> Commit 871af1210f13966ab911ed2166e4ab2ce775b99d (libata: Add 32bit PIO support) >> caused all kind of errors on the ATAPI devices, so it's been empirically proven >> that one shouldn't read/write an extra data word when a device isn't expecting >> it already. "Don't do it then"; however still taking a chance to use 32-bit I/O >> one last time when there are exactly 3 trailing bytes. Oh, and stop pointless >> swapping bytes to and fro as well by using io*_rep() which shouldn't byte-swap. >> >> This should fix the kernel.org bug #12609. >> >> --- >> This is hopefully better replacement for Hugh Dickins most recent patch >> (http://marc.info/?l=linux-ide&m=123352294619281)... >> > > Yes, looks nice, and works for me. My only criticism would be, > minor issue unchanged by your patch, that actually "slop" isn't > unlikely enough to deserve an "unlikely" - slop of 1 or 3 is > unlikely, but slop of 2 is quite common. > Common on what types of ATAPI commands? I can hardly believe that they are common on the block I/O... MBR, Sergei