From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH 02/20] ata_piix: unify code for programming PIO and MWDMA timings Date: Mon, 21 Feb 2011 14:59:08 +0300 Message-ID: <4D62538C.1010200@ru.mvista.com> References: <20110208122314.19110.4092.sendpatchset@linux-mhg7.site> <20110208122346.19110.8441.sendpatchset@linux-mhg7.site> <4D6118DC.80505@ru.mvista.com> <20110220185958.364df4cc@lxorguk.ukuu.org.uk> <4D617CC8.3020108@ru.mvista.com> <20110220210731.0c774fa7@lxorguk.ukuu.org.uk> <4D624EBD.4080400@ru.mvista.com> <20110221115839.2048e8fe@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ew0-f42.google.com ([209.85.215.42]:62671 "EHLO mail-ew0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755428Ab1BUMA2 (ORCPT ); Mon, 21 Feb 2011 07:00:28 -0500 In-Reply-To: <20110221115839.2048e8fe@lxorguk.ukuu.org.uk> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: Sergei Shtylyov , Bartlomiej Zolnierkiewicz , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Hello. On 21-02-2011 14:58, Alan Cox wrote: >>>> PIO mode is setup by different code, and it takes care of the IORDY >>>> setting according to the PIO rules (and it gets called). DMA mode setup should >>>> just ignore the IORDY setting as in all other sane drivers. >>> Well it can't ignore it - but if you mean just keep the bit as is then >> Yes, I mean this. >>> that sounds sensible, have to see what the docs say happens if you ever >>> set MWDMA without IORDY. >> Don't think they say anything on this matter but I can't imagine that >> IORDY matters for DMA. ... unless the IE bit means something special (and undocumented) for DMA, if Intel so insists on setting it for every DMA mode. > Sure - but it does matter for an ATAPI transaction with then has a DMA > phase because those timings will be used for the command transfer which > is PIO. So what? We've already setup PIO timings before the DMA ones. Why force the IE bit? > Alan WBR, Sergei