Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751673AbWIAPyG (ORCPT ); Fri, 1 Sep 2006 11:54:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751702AbWIAPyF (ORCPT ); Fri, 1 Sep 2006 11:54:05 -0400 Received: from 85.8.24.16.se.wasadata.net ([85.8.24.16]:20875 "EHLO smtp.drzeus.cx") by vger.kernel.org with ESMTP id S1751673AbWIAPyD (ORCPT ); Fri, 1 Sep 2006 11:54:03 -0400 Message-ID: <44F85797.9070208@drzeus.cx> Date: Fri, 01 Sep 2006 17:53:59 +0200 From: Pierre Ossman User-Agent: Thunderbird 1.5.0.5 (X11/20060803) MIME-Version: 1.0 To: Ian Stirling CC: madhu chikkature , linux-kernel@vger.kernel.org Subject: Re: SDIO card support in Linux References: <44F73E37.6030602@drzeus.cx> <44F85646.4030100@mauve.plus.com> In-Reply-To: <44F85646.4030100@mauve.plus.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 890 Lines: 27 Ian Stirling wrote: >> >> SD mandates a star topology (just a single card per bus), so we'll just >> force a single card into the list. SD memory cards can actually work on >> a shared bus, SDIO can not. It's not a big problem in practice though. > > Is this true in SD-1 bit mode, or SPI? Yes, no. :) > I see nothing on a quick read-through of the abbreviated SDIO spec > precluding this. > Of course, it'd mean wire-or'd interrupt lines. > The problem is that there is no "king-of-the-hill" mechanism in the SDIO init sequence (like there is in SD mem). The protocol assumes that the desired card always receives the command. Rgds Pierre - 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/