From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Madhusudhan" Subject: RE: simple sd card performance bug fix on OMAP Date: Fri, 28 May 2010 14:53:02 -0500 Message-ID: <006801cafe9f$6209e030$544ff780@am.dhcp.ti.com> References: <4C0013DC.6060601@earthlink.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from bear.ext.ti.com ([192.94.94.41]:48562 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755774Ab0E1TxF (ORCPT ); Fri, 28 May 2010 15:53:05 -0400 In-Reply-To: <4C0013DC.6060601@earthlink.net> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "'Stephen Schwarm, CSDP'" , linux-omap@vger.kernel.org > -----Original Message----- > From: linux-omap-owner@vger.kernel.org [mailto:linux-omap- > owner@vger.kernel.org] On Behalf Of Stephen Schwarm, CSDP > Sent: Friday, May 28, 2010 2:05 PM > To: linux-omap@vger.kernel.org > Subject: simple sd card performance bug fix on OMAP > > I have not had time to make a formal patch for this but I thought it was > significant enough just to send it out. The problem is on omap systems > that use omap_hsmmc.c to run sd or mmc cards. If the system you are > using has an 8 wire interface, it will only use a one wire interface to > 4 wire cards (eg, sd class 4 and sd class 6). > A patch to fix this was already posted on LO by Kishore. Regards, Madhu > In the file driver/mmc/omap_hsmmc.c in the function omap_hsmmc_probe: > at about line 1739 change: > > if (mmc_slot(host).wires >= 8) > mmc->caps |= MMC_CAP_8_BIT_DATA; > else if (mmc_slot(host).wires >= 4) > mmc->caps |= MMC_CAP_4_BIT_DATA; > > to: > > if (mmc_slot(host).wires >= 8) > mmc->caps |= MMC_CAP_8_BIT_DATA; > if (mmc_slot(host).wires >= 4) > mmc->caps |= w; > > just delete the word "else". This sets the MMC_CAP_4_BIT_DATA bit on > interfaces that have 8 wire interfaces. > > We have seen a BIG performance improvement on our systems. > > Steve Schwarm >