From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Ball Subject: Re: [BUG] CMD52 sent as first command not CMD0 Date: Sun, 6 Feb 2011 00:38:45 +0000 Message-ID: <20110206003845.GA15019@void.printf.net> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from void.printf.net ([89.145.121.20]:33776 "EHLO void.printf.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751684Ab1BFAiu (ORCPT ); Sat, 5 Feb 2011 19:38:50 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Philip Rakity Cc: "linux-mmc@vger.kernel.org" , Albert Herranz Hi Philip, On Fri, Feb 04, 2011 at 02:53:59PM -0800, Philip Rakity wrote: > using mmc-next -- NO changes -- last checkin was from linux Jan 26 [..] > [ 2.034998] mmc0: starting CMD52 arg 00000c00 flags 00000195 > [ 2.052704] Waiting 15sec before mounting root device... > [ 2.068948] sdhci [sdhci_irq()]: *** mmc0 got interrupt: 0x00018000 > [ 2.087707] mmc0: req done (CMD52): -110: 00000000 00000000 00000000 00000000 > [ 2.109069] mmc0: starting CMD52 arg 80000c08 flags 00000195 > [ 2.126291] sdhci [sdhci_irq()]: *** mmc0 got interrupt: 0x00018000 > [ 2.145002] mmc0: req done (CMD52): -110: 00000000 00000000 00000000 00000000 > [ 2.166321] mmc0: clock 400000Hz busmode 1 powermode 2 cs 1 Vdd 21 width 0 timing 0 > [ 2.190178] mmc0: starting CMD0 arg 00000000 flags 000000c0 > [ 2.206971] sdhci [sdhci_irq()]: *** mmc0 got interrupt: 0x00000001 > [ 2.225689] mmc0: req done (CMD0): 0: 00000000 00000000 00000000 00000000 This looks to be intentional, and dates back to: commit 516a82422209e078345d0ca54b16793d7bfd4782 Author: Albert Herranz Date: Wed Mar 10 15:20:37 2010 -0800 sdio: recognize io card without powercycle SDIO Simplified Specification V2.00 states that it is strongly recommended that the host executes either a power reset or issues a CMD52 (I/O Reset) to re-initialize an I/O only card or the I/O portion of a combo card. Additionally, the CMD52 must be issued first because it cannot be issued after a CMD0. With this patch the Nintendo Wii SDIO-based WLAN card is detected after a system reset, without requiring a complete system powercycle. Are you seeing any negative effects from running the CMD52 before CMD0? Thanks, -- Chris Ball One Laptop Per Child