From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756032Ab0CaHDG (ORCPT ); Wed, 31 Mar 2010 03:03:06 -0400 Received: from mail-fx0-f223.google.com ([209.85.220.223]:44941 "EHLO mail-fx0-f223.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750962Ab0CaHDD (ORCPT ); Wed, 31 Mar 2010 03:03:03 -0400 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; b=whNnou/ZS7jGuAk6FmQIrmxUnKfxjO4AT3/YvjAbzKEimqlwu75UADaU1kHQxk0FXq H4c3hwUzbpy0P50s+iSl2S6sghFlwIjxTYHtxFKYbFupZ6Z0F5TKZs+SV5ceid52FjQg Ups97tRwTlPDLdtdFEnRSAG8grm41iXE9dXw0= MIME-Version: 1.0 In-Reply-To: References: <35697.192.168.10.89.1265898023.squirrel@dbdmail.itg.ti.com> <004701caab40$68b576e0$544ff780@am.dhcp.ti.com> Date: Wed, 31 Mar 2010 12:33:01 +0530 Message-ID: Subject: Re: [PATCH-V2] OMAP: Fix for bus width which improves SD card's peformance. From: kishore kadiyala To: Vimal Singh Cc: Madhusudhan , tony@atomide.com, svenkatr@ti.com, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, jarkko.lavinen@nokia.com Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sorry for that and here's the Updated one. From: Kishore Kadiyala This patch improves low speeds for SD cards. OMAP-MMC controller's can support maximum bus width of '8'. when bus width is mentioned as "8" in controller data,the SD stack will check whether bus width is "4" and if not it will set bus width to "1" and there by degrading performance. This patch fixes the issue and improves the performance of SD cards. Signed-off-by: Kishore Kadiyala Signed-off-by: Venkatraman S Acked-by: Madhusudhan Chikkature --- In V2 : Appended Signed-off by Venkat and Ack by Madhu Here are my experiment numbers, on a Class 6 SDHC card: Read peformance is increased by 220% Write Performance is increased by 52% drivers/mmc/host/omap_hsmmc.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c index 83f0aff..8c97c22 100644 --- a/drivers/mmc/host/omap_hsmmc.c +++ b/drivers/mmc/host/omap_hsmmc.c @@ -2092,7 +2092,7 @@ static int __init omap_hsmmc_probe(struct MMC_CAP_WAIT_WHILE_BUSY; if (mmc_slot(host).wires >= 8) - mmc->caps |= MMC_CAP_8_BIT_DATA; + mmc->caps |= (MMC_CAP_8_BIT_DATA | MMC_CAP_4_BIT_DATA); else if (mmc_slot(host).wires >= 4) mmc->caps |= MMC_CAP_4_BIT_DATA; -- 1.6.3.3