Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760545AbYFIKnd (ORCPT ); Mon, 9 Jun 2008 06:43:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759452AbYFIKnZ (ORCPT ); Mon, 9 Jun 2008 06:43:25 -0400 Received: from server.drzeus.cx ([85.8.24.28]:33030 "EHLO smtp.drzeus.cx" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753001AbYFIKnY (ORCPT ); Mon, 9 Jun 2008 06:43:24 -0400 Date: Mon, 9 Jun 2008 12:42:49 +0200 From: Pierre Ossman To: Russell King - ARM Linux Cc: Nicolas Ferre , Linux Kernel list , Andrew Victor , Eric BENARD , ARM Linux Mailing List Subject: Re: [PATCH 4/7] mmc: at91_mci: add multiwrite switch Message-ID: <20080609124249.349995df@mjolnir.drzeus.cx> In-Reply-To: <20080601144251.GS5818@flint.arm.linux.org.uk> References: <483FE9E7.7020707@atmel.com> <483FEE58.5000500@atmel.com> <20080601144251.GS5818@flint.arm.linux.org.uk> X-Mailer: Claws Mail 3.4.0 (GTK+ 2.13.2; i386-redhat-linux-gnu) Face: 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 X-Face: @{|$W51qEixc&6}dq_38NM^&.vv|'{O)ae?DMZ1%VYxuhN2}5VpQ!'gx[{V+8Xw'+cV5*491_)-SU2YT8s@4`H;@:ELS'/P(@.JxxJi/C8mG0H#A^R X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1816 Lines: 48 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-12279-1213007847-0001-2 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Sun, 1 Jun 2008 15:42:52 +0100 Russell King - ARM Linux wrote: > If Pierre wants to remove the MULTIWRITE flag, I'd like to hear his > solution for the pxamci driver, where the only way to ascertain how > many bytes were transmitted may be to walk the SG list comparing the > DMA pointer with what was in the hardware DMA engine at the time. > Maybe. You set bytes_xfered to 0. As mentioned in my previous mail, I had a chat with Jens about this and upper layers can only expect to get the lower bound in how many bytes were written. Other hardware/drivers already behaves like this so there is no point in crippling the MMC layer in an effort to give nicer guarantees. This is why I asked people to audit their drivers to make sure it's the lower bound that's returned, but I've not received much in the way of replies. Rgds Pierre --=_freyr.drzeus.cx-12279-1213007847-0001-2 Content-Type: application/pgp-signature; name="signature.asc" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) iEYEARECAAYFAkhNCTEACgkQ7b8eESbyJLgW8wCfdgZOxmodiE/Nnw1Bt73OTXFJ rngAnjpQwn1wFz8YimKacS1Z0USQINTp =TYf9 -----END PGP SIGNATURE----- --=_freyr.drzeus.cx-12279-1213007847-0001-2-- -- 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/