Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753356AbbEHV1K (ORCPT ); Fri, 8 May 2015 17:27:10 -0400 Received: from skprod3.natinst.com ([130.164.80.24]:55257 "EHLO ni.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752896AbbEHV1G (ORCPT ); Fri, 8 May 2015 17:27:06 -0400 Date: Fri, 8 May 2015 16:26:32 -0500 From: Ben Shelton To: Brian Norris Cc: punnaiah choudary kalluri , Richard Weinberger , "linux-mtd@lists.infradead.org" , "linux-kernel@vger.kernel.org" , David Woodhouse , Punnaiah Choudary Kalluri , Boris Brezillon Subject: Re: [PATCH 1/3] mtd: nand: Add on-die ECC support Message-ID: <20150508212632.GA7167@bshelton-desktop> References: <1427292151-3835-1-git-send-email-richard@nod.at> <1427292151-3835-2-git-send-email-richard@nod.at> <20150427213558.GA22780@bshelton-desktop> <553EB5E4.3050309@nod.at> <20150427232353.GD32500@ld-irv-0074> <20150428032213.GI19571@brian-ubuntu> MIME-Version: 1.0 In-Reply-To: <20150428032213.GI19571@brian-ubuntu> User-Agent: Mutt/1.5.21 (2010-09-15) X-MIMETrack: Itemize by SMTP Server on US-AUS-MGWOut2/AUS/H/NIC(Release 8.5.3FP6|November 21, 2013) at 05/08/2015 04:26:34 PM, Serialize by Router on US-AUS-MGWOut2/AUS/H/NIC(Release 8.5.3FP6|November 21, 2013) at 05/08/2015 04:26:35 PM, Serialize complete at 05/08/2015 04:26:35 PM Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2015-05-08_07:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1878 Lines: 45 On 04/27, Brian Norris wrote: > On Tue, Apr 28, 2015 at 08:18:12AM +0530, punnaiah choudary kalluri wrote: > > On Tue, Apr 28, 2015 at 4:53 AM, Brian Norris > > wrote: > > > On Tue, Apr 28, 2015 at 12:19:16AM +0200, Richard Weinberger wrote: > > >> Oh, I thought every driver has to implement that function. ;-\ > > > > > > Nope. > > > > > >> But you're right there is a corner case. > > > > > > And it's not the only one! Right now, there's no guarantee even that > > > read_buf() returns raw data, unmodified by the SoC's controller. Plenty > > > of drivers actually have HW-enabled ECC turned on by default, and so > > > they override the chip->ecc.read_page() (and sometimes > > > chip->ecc.read_page_raw() functions, if we're lucky) with something > > > that pokes the appropriate hardware instead. I expect anything > > > comprehensive here is probably going to have to utilize > > > chip->ecc.read_page_raw(), at least if it's provided by the hardware > > > driver. > > > > Yes, overriding the chip->ecc.read_page_raw would solve this. > > I'm actually suggesting that (in this patch set, for on-die ECC > support), maybe we *shouldn't* override chip->ecc.read_page_raw() and > leave that to be defined by the driver, and then on-die ECC support > should be added in a way that just calls chip->ecc.read_page_raw(). This > should work for any driver that already properly supports the raw > callbacks. > Hi Richard et al, I'm guessing it's probably too late for the on-die ECC stuff to land in 4.2 at this point. Is there anything I can do to help this along (testing, etc.)? Thanks, Ben -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/