From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.nokia.com ([192.100.122.230] helo=mgw-mx03.nokia.com) by bombadil.infradead.org with esmtps (Exim 4.68 #1 (Red Hat Linux)) id 1Joy9W-0007kU-Te for linux-mtd@lists.infradead.org; Thu, 24 Apr 2008 09:54:07 +0000 Subject: Re: [RFC][patch] NAND partial page read functionality From: Artem Bityutskiy To: Hamish Moffatt In-Reply-To: <20080424074526.GA21709@cloud.net.au> References: <1209018876.11721.100.camel@sauron> <20080424074526.GA21709@cloud.net.au> Content-Type: text/plain; charset=utf-8 Date: Thu, 24 Apr 2008 12:53:59 +0300 Message-Id: <1209030839.11721.115.camel@sauron> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Cc: dwmw2@infradead.org, Thomas Gleixner , linux-mtd@lists.infradead.org, Alexey Korolev Reply-To: dedekind@infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2008-04-24 at 17:45 +1000, Hamish Moffatt wrote: > The rest of the discussion was about improved use of sub-page writes. > I'm sure that would be useful but it's not strictly relevant to the > partial read patch. Yup. > Artem, were you able to try the patch on the OLPC with hardware ECC, as > you hinted in the original discussion? Right, I completely forgot to do this. I've just verified - OLPC works just fine with this patch. It also does not affect our OneNAND setup. > Also I reverted your recent patch to combine the EC + VID header reads > in the UBI scan for this test. I think with partial reads it may make=20 > things slower, because it will force 2K to be read (or 576 bytes if the=20 > ALIGN() is removed, still more than 64 + 64). Because min_io_size =3D 2K > is not really accurate I guess. I deliberately did that. I though making one call instead of 2 is better, because MTD anyway reads whole page. And my other motivation was that flashes like OneNAND which may read 2 consecutive pages faster (kind of "burst" read). Although for OneNAND this trick does not really work. Anyway, lets forget about that patch. I think if Alexey is not any more interested in working on his patch, you could do this, if you are interested. I am going to be away till the 5 of May, so I won't be able to help. --=20 Best regards, Artem Bityutskiy (=D0=91=D0=B8=D1=82=D1=8E=D1=86=D0=BA=D0=B8=D0=B9 =D0=90= =D1=80=D1=82=D1=91=D0=BC)