From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH] libata: add support for READ/WRITE LONG Date: Fri, 16 Mar 2007 17:16:35 +0300 Message-ID: <45FAA6C3.8090209@ru.mvista.com> References: <3aac340703102322p362998b9labedc13503702d2b@mail.gmail.com> <45F56800.3040104@rtr.ca> <3aac340703121003l43685599t8dbffe6247879a91@mail.gmail.com> <45F5A523.1080500@rtr.ca> <45FA8D7A.3040504@rtr.ca> <45FAA35C.2090902@ru.mvista.com> <20070316151508.543486ec@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from h155.mvista.com ([63.81.120.155]:33244 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752169AbXCPOQs (ORCPT ); Fri, 16 Mar 2007 10:16:48 -0400 In-Reply-To: <20070316151508.543486ec@lxorguk.ukuu.org.uk> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: Mark Lord , Jeff Garzik , Vitaliyi , Tejun Heo , IDE/ATA development list Hello. Alan Cox wrote: >> Which requires from the drivers to be able to turn off IDE prefetch (and >>maybe posting too). I don't see that in this patch (or are you expecting them >>to just "snoop' the commands and do it automagically?). > We need to see which drivers have that problem and if its only the odd > one then we can handle it in qc_issue. We've already got controllers that > wrap qc_issue to peek at commands and reject some of them (eg the 8212 in > hardware raid mode) I'd expect this to be needed with all drives, since IIUC prefetch is working based on either fixed or programmable sector size. And here the out-of-band PIO protocol itself (which fails to be taken into account by the patch) implies mixed 8- and 16- bit I/O which should also be muddling up the prefetch logic. > Alan WBR, Sergei