From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 1/2] ide: Add tx4939ide driver Date: Sat, 04 Oct 2008 11:56:21 +0900 Message-ID: <48E6DB55.2050800@gmail.com> 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> <1222787387.3232.26.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from ti-out-0910.google.com ([209.85.142.184]:12233 "EHLO ti-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752004AbYJDC6L (ORCPT ); Fri, 3 Oct 2008 22:58:11 -0400 Received: by ti-out-0910.google.com with SMTP id b6so829148tic.23 for ; Fri, 03 Oct 2008 19:58:09 -0700 (PDT) In-Reply-To: <1222787387.3232.26.camel@localhost.localdomain> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: James Bottomley 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 James Bottomley wrote: > 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. The thread Atsushi found seems to be the correct one. http://lkml.org/lkml/2006/1/13/156 Thanks. -- tejun