From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750744AbWFEWwj (ORCPT ); Mon, 5 Jun 2006 18:52:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750746AbWFEWwj (ORCPT ); Mon, 5 Jun 2006 18:52:39 -0400 Received: from 85.8.24.16.se.wasadata.net ([85.8.24.16]:48779 "EHLO smtp.drzeus.cx") by vger.kernel.org with ESMTP id S1750744AbWFEWwi (ORCPT ); Mon, 5 Jun 2006 18:52:38 -0400 Message-ID: <4484B5AE.8060404@drzeus.cx> Date: Tue, 06 Jun 2006 00:52:30 +0200 From: Pierre Ossman User-Agent: Thunderbird 1.5.0.2 (X11/20060420) MIME-Version: 1.0 CC: Matt Reimer , linux-kernel@vger.kernel.org Subject: Re: 2GB MMC/SD cards References: <447AFE7A.3070401@drzeus.cx> <20060603141548.GA31182@flint.arm.linux.org.uk> <4481FB80.40709@drzeus.cx> In-Reply-To: <4481FB80.40709@drzeus.cx> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: unlisted-recipients:;;@mail-zipworld.pacific.net.au (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Pierre Ossman wrote: > Matt Reimer wrote: >> I suspect that a lot of these readers are broken, assuming 512 byte >> blocks. >> > > That's what I thought until I looked closer at the Sandisk specs. Until > we can see what the official specs say, we won't really know what the > correct behaviour is. The Nokia boys working on the 770 have a copy. > Perhaps someone here knows how to get in touch with one of them that can > have a look? > With the help of Khasim Syed, who happens to have access to the MMC spec, we now know what's in the spec. Unfortunately, what's in there is the same text that's in Russell's card specs, which state that only WRITE_BL_LEN is supported. However! In the simplified SD physical spec (which you can find on the SDA home page), we can find: 4.3.2 2GByte Card To make 2GByte card, the Maximum Block Length (READ_BL_LEN=WRITE_BL_LEN) shall be set to 1024 bytes. But Block Length set by CMD16 shall be up to 512 bytes to keep consistency with 512 bytes Maximum Block Length cards (Less than and equal 2GByte cards). It even has an example with WRITE_BL_PARTIAL=0, still setting block length to 512. Now I know this is SD and not MMC, but the debug dump from Serge earlier seems to suggest that MMC cards follow the same rule. Even though this breaks the MMC spec, my vote is for 512 bytes at all times. If the entire industry decided to violate the spec, I don't see much gain in being stubborn here. Rgds Pierre