Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752714AbZCHOVj (ORCPT ); Sun, 8 Mar 2009 10:21:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752045AbZCHOVa (ORCPT ); Sun, 8 Mar 2009 10:21:30 -0400 Received: from 82-117-125-11.tcdsl.calypso.net ([82.117.125.11]:40720 "EHLO smtp.drzeus.cx" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751930AbZCHOVa (ORCPT ); Sun, 8 Mar 2009 10:21:30 -0400 Date: Sun, 8 Mar 2009 15:21:20 +0100 From: Pierre Ossman To: avorontsov@ru.mvista.com Cc: Ben Dooks , Arnd Bergmann , Kumar Gala , Liu Dave , sdhci-devel@list.drzeus.cx, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org Subject: Re: [PATCH 12/13] sdhci: Add quirk for controllers with max. block size up to 4096 bytes Message-ID: <20090308152120.38deb08b@mjolnir.ossman.eu> In-Reply-To: <20090304174744.GB7477@oksana.dev.rtsoft.ru> References: <20090213144630.GA13436@oksana.dev.rtsoft.ru> <20090213144739.GL23889@oksana.dev.rtsoft.ru> <20090221165844.4f494043@mjolnir.ossman.eu> <20090304174744.GB7477@oksana.dev.rtsoft.ru> X-Mailer: Claws Mail 3.7.0 (GTK+ 2.15.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; protocol="application/pgp-signature"; boundary="=_freyr.drzeus.cx-22064-1236522085-0001-2" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2351 Lines: 67 This is a MIME-formatted message. If you see this text it means that your E-mail software does not support MIME-formatted messages. --=_freyr.drzeus.cx-22064-1236522085-0001-2 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 4 Mar 2009 20:47:44 +0300 Anton Vorontsov wrote: >=20 > I'll get rid of this particular patch, and put some BLOCK_SIZE > magic into the writew accessor (to clean the DMA bits) instead. >=20 > Though, I'll prepare another patch to force blksz to 2048, since > eSDHC specifies "3" in the blksz capability bitfield, and that > causes SDHCI core to fall back to the 512 byte blocks. >=20 Ok. > > After all, is it ever used? >=20 > Not sure, maybe `dd bs=3D' can use it? A bit lazy to check this > right now, but from the quick tests, enabling/disabling "blksz > of 4096 bytes" doesn't cause any performance change. At least > with the ordinary SD cards. >=20 Memory cards will not use this (at least not with the current standards), as the block layer thinks in 512 byte blocks. Also, the sector size propagates to user space in a way that causes filesystems to behave differently, making cards incompatible with all other operating systems (i.e. if we don't use 512 byte blocks). So the only scenario where this might be used is SDIO, and I'm not sure such big blocks are a win there either because of the overhead of changing block size. Rgds --=20 -- Pierre Ossman WARNING: This correspondence is being monitored by the Swedish government. Make sure your server uses encryption for SMTP traffic and consider using PGP for end-to-end encryption. --=_freyr.drzeus.cx-22064-1236522085-0001-2 Content-Type: application/pgp-signature; name="signature.asc" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.11 (GNU/Linux) iEYEARECAAYFAkmz1GIACgkQ7b8eESbyJLhTfwCdEb94fpg8zMP799gEvcK6mzxd omMAoL3BAmCZ4lBj5T91PH11e7It/950 =7CIh -----END PGP SIGNATURE----- --=_freyr.drzeus.cx-22064-1236522085-0001-2-- -- 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/