From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [comments] MMC: Reliable write support. Date: Wed, 30 Mar 2011 14:05:20 +0200 Message-ID: <201103301405.21047.arnd@arndb.de> References: <1301001751-30785-1-git-send-email-andreiw@motorola.com> <201103290901.31680.arnd@arndb.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.17.10]:57910 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754803Ab1C3MF0 (ORCPT ); Wed, 30 Mar 2011 08:05:26 -0400 In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Andrei Warkentin Cc: linux-mmc@vger.kernel.org, Chris Ball On Wednesday 30 March 2011, Andrei Warkentin wrote: > On Tue, Mar 29, 2011 at 2:01 AM, Arnd Bergmann wrote: > > On Tuesday 29 March 2011, Andrei Warkentin wrote: > >> On Fri, Mar 25, 2011 at 10:14 AM, Arnd Bergmann wrote: > >> > >> I confirmed with two MMC vendors that there is no "flush". Once the > >> DAT transfer completes, the data is stored on non-volatile storage as > >> soon as the busy status is cleared. > >> > >> Reliable writes are still "more reliable" because if the DAT transfer > >> is interrupted (power or reset through CMD0/CMD15 or hw pin for eMMC), > >> you have predictable flash contents. So it makes sense to map REQ_FUA > >> to it (and REQ_META, I would guess). > > > > Yes, sounds good. > > > > So I guess on MLC flash, a reliable write will go to a flash page > > that does not have data in any of its paired pages. > > Should I resubmit the patch? I think the patch was ok, you can add my Reviewed-by: Arnd Bergmann Chris, what is your opinion on the patch? Arnd