Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751336Ab0LUK7K (ORCPT ); Tue, 21 Dec 2010 05:59:10 -0500 Received: from mail-fx0-f43.google.com ([209.85.161.43]:47083 "EHLO mail-fx0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750805Ab0LUK7H convert rfc822-to-8bit (ORCPT ); Tue, 21 Dec 2010 05:59:07 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=RxG79p3pgS/wjFvtXsHS57XWuTAGpekjRXSnAYriKuHN5+cKezuF+u6At3oXCUs6WD cnPVZsx+yLCM0An9qk6fD6iUju2Wn95e/HZuKPUzk0MT/FQKFdUYKApOGG4MR72sLX5l 37AsjV1PxbPq+6h91Gkr+R+dMPtyBZjFWC3MY= MIME-Version: 1.0 In-Reply-To: References: <20101216234032.GA17239@void.printf.net> <50D31EC8-BD9E-4920-8CEB-2AD10DF9C5C5@marvell.com> <20101217034342.GA19673@void.printf.net> Date: Tue, 21 Dec 2010 05:59:06 -0500 Message-ID: Subject: Re: [PATCH] mmc: Test bus-width for old MMC devices (v2) From: zhangfei gao To: Takashi Iwai Cc: Chris Ball , Philip Rakity , Aries Lee , Qiming Wu , "linux-mmc@vger.kernel.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2129 Lines: 71 On Fri, Dec 17, 2010 at 3:11 AM, Takashi Iwai wrote: > At Fri, 17 Dec 2010 03:43:42 +0000, > Chris Ball wrote: >> >> Hi Philip, >> >> On Thu, Dec 16, 2010 at 06:33:49PM -0800, Philip Rakity wrote: >> > It is not possible for bus_width to be not initialized. ?This would imply ARRAY_SIZE(bus_widths) is 1. ?Certainly not true. >> >> Right, I agree. ?We should fix the warning anyway. > > Well, this is always a gray-zone question. ?One prefers fixing it > either via uninitialized_var() or by setting a bogus value. ?But, this > would cover any possible real bug in future. ?Thus another prefers > ignoring it, because it's just a compiler bug (mostly of old gcc). > > After all, it's up to maintainer, so take as you like :) > > > thanks, > > Takashi > > >> > We could just initialize by changing >> > + ? ? ? ? ? unsigned idx, bus_width; >> > to >> > + ? ? ? ? ? unsigned idx, bus_width = 0; >> >> Okay, I've pushed to mmc-next with that change. >> >> > I wonder what compiler are you using so we can avoid this issue in future. >> >> Ah, good point -- I was building with a gcc 4.1.2 ARM cross-compiler, >> and using a gcc 4.5.1 cross-build instead avoids the warning. >> >> Thanks, >> >> -- >> Chris Ball ? ? >> One Laptop Per Child >> > Could you help adding this modification? We found error happen since bus_width is not set at these condition: 1. ddr=0 2. not set MMC_CAP_BUS_WIDTH_TEST diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index 1d8409f..86cac0d 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -586,7 +586,11 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, } else if (ddr) { mmc_card_set_ddr_mode(card); mmc_set_bus_width_ddr(card->host, bus_width, ddr); - } + + } else + mmc_set_bus_width(card->host, + bus_widths[idx]); + } if (!oldcard) -- 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/