Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753653Ab0DAGb7 (ORCPT ); Thu, 1 Apr 2010 02:31:59 -0400 Received: from mail-fx0-f227.google.com ([209.85.220.227]:57103 "EHLO mail-fx0-f227.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753486Ab0DAGbw convert rfc822-to-8bit (ORCPT ); Thu, 1 Apr 2010 02:31:52 -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:content-transfer-encoding; b=XCg0H41Mg2g3t5CaAITrgit5WzkBQOedoJwSr5PmjNvwY04tu5bkL5QrDPXyjZZVCY d18foELNFN7MgMPQuIwVOhw2uKotC8MCPVZIMMVJUMMyX3CejLa/w+X2i+3l2OGYVvhS DxD65mMSQCflz+Md3TKxAzejMJRcGkYkRjGEA= MIME-Version: 1.0 In-Reply-To: <003b01cad0f0$6ea78040$544ff780@am.dhcp.ti.com> References: <35697.192.168.10.89.1265898023.squirrel@dbdmail.itg.ti.com> <004701caab40$68b576e0$544ff780@am.dhcp.ti.com> <003b01cad0f0$6ea78040$544ff780@am.dhcp.ti.com> Date: Thu, 1 Apr 2010 12:01:49 +0530 Message-ID: Subject: Re: [PATCH-V2] OMAP: Fix for bus width which improves SD card's peformance. From: kishore kadiyala To: Madhusudhan Cc: Vimal Singh , 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 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2951 Lines: 89 On Wed, Mar 31, 2010 at 10:07 PM, Madhusudhan wrote: > > >> -----Original Message----- >> From: kishore kadiyala [mailto:kishorek.kadiyala@gmail.com] >> Sent: Wednesday, March 31, 2010 2:03 AM >> 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 >> Subject: Re: [PATCH-V2] OMAP: Fix for bus width which improves SD card's >> peformance. >> >> 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; >> > Kishore, > > Since this patch is not yet pushed it makes sense to fix the readability > issue. > > Since 8-bit is the max how about: > > ?? ? ? ?if (mmc_slot(host).wires == 8) > ?? ? ? ? ? ? ? ?mmc->caps |= MMC_CAP_8_BIT_DATA | MMC_CAP_4_BIT_DATA; > ?? ? ? ?if (mmc_slot(host).wires == 4) > ?? ? ? ? ? ? ? ?mmc->caps |= MMC_CAP_4_BIT_DATA; > Madhu, In the above snippet, it checks whether wires are 8 or 4 and if not neither set's capability to "1". Does it make sense to check whether the wires are 8,4,1 and if not any[8,4,1] throw error and come out. Regards, Kishore > This would be little easy to read the code. > > Can you please repost the patch?? > > Regards, > Madhu > >> -- >> 1.6.3.3 > > -- 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/