From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [PATCH 1/2] ide: Add tx4939ide driver Date: Tue, 30 Sep 2008 10:09:47 -0500 Message-ID: <1222787387.3232.26.camel@localhost.localdomain> References: <48C851ED.4090607@ru.mvista.com> <48CA8BEE.1090305@ru.mvista.com> <20080913.005904.07457691.anemo@mba.ocn.ne.jp> <200809271819.19510.bzolnier@gmail.com> <48DEAF1F.8040200@gmail.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from accolon.hansenpartnership.com ([76.243.235.52]:43426 "EHLO accolon.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751767AbYI3PKS (ORCPT ); Tue, 30 Sep 2008 11:10:18 -0400 In-Reply-To: <48DEAF1F.8040200@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: Bartlomiej Zolnierkiewicz , Atsushi Nemoto , sshtylyov@ru.mvista.com, linux-mips@linux-mips.org, linux-ide@vger.kernel.org, ralf@linux-mips.org, Jens Axboe On Sun, 2008-09-28 at 07:09 +0900, Tejun Heo wrote: > Bartlomiej Zolnierkiewicz wrote: > > On Friday 12 September 2008, Atsushi Nemoto wrote: > >> On Fri, 12 Sep 2008 19:34:06 +0400, Sergei Shtylyov wrote: > > > > [...] > > > >>>>>> + __ide_flush_dcache_range((unsigned long)addr, size); > >>>>> Why is this needed BTW? > >>>> Do you mean __ide_flush_dcache_range? This is needed to avoid cache > >>>> inconsistency on PIO drive. PIO transfer only writes to cache but > >>>> upper layers expects the data is in main memory. > >>> Hum, then I wonder why it's MIPS specific... > >> SPARC also have it. And there were some discussions for ARM IIRC. > > > > I was under the impression that it has been addressed by Tejun at > > the higher-layer level (for both ide/libata) long time ago and that > > MIPS/SPARC code are just a left-overs which could be removed now? > > cc'ing Jens and James. IIRC, I posted several patches but they never > went in. I don't remember what the objections were or whether any > alternative fix went in. Which patches were these? We have several methods of doing PIO fallback, the most common one being scatterlist.c:sg_copy_from/to_buffer() which does the cache coherency. James > Thanks. >