From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Madhusudhan" Subject: RE: simple sd card performance bug fix on OMAP Date: Thu, 10 Jun 2010 10:31:07 -0500 Message-ID: <005001cb08b1$f349ba40$544ff780@am.dhcp.ti.com> References: <4C0013DC.6060601@earthlink.net> <5A47E75E594F054BAF48C5E4FC4B92AB032162380F@dbde02.ent.ti.com> <007601cb0277$afa019a0$544ff780@am.dhcp.ti.com> <20100610063621.GP32208@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from arroyo.ext.ti.com ([192.94.94.40]:44674 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751893Ab0FJPbl (ORCPT ); Thu, 10 Jun 2010 11:31:41 -0400 In-Reply-To: <20100610063621.GP32208@atomide.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: 'Tony Lindgren' Cc: "'Gadiyar, Anand'" , "'Stephen Schwarm, CSDP'" , linux-omap@vger.kernel.org > -----Original Message----- > From: Tony Lindgren [mailto:tony@atomide.com] > Sent: Thursday, June 10, 2010 1:36 AM > To: Madhusudhan > Cc: 'Gadiyar, Anand'; 'Stephen Schwarm, CSDP'; linux-omap@vger.kernel.org > Subject: Re: simple sd card performance bug fix on OMAP > > * Madhusudhan [100602 20:13]: > > > > > > > -----Original Message----- > > > From: linux-omap-owner@vger.kernel.org [mailto:linux-omap- > > > owner@vger.kernel.org] On Behalf Of Gadiyar, Anand > > > Sent: Friday, May 28, 2010 2:55 PM > > > To: Stephen Schwarm, CSDP; linux-omap@vger.kernel.org > > > Subject: RE: simple sd card performance bug fix on OMAP > > > > > > Stephen Schwarm, CSDP wrote: > > > > > > > > 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). > > > > > > > > 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. > > > > > > > > > > Thanks for reporting this. > > > > > > A similar patch was posted a while ago and is currently marked as > > > "awaiting upstream", although it looks like it got lost again. > > > > > > > > > > > A revised version of the same patch was posted. > > > > https://patchwork.kernel.org/patch/93519/ > > > > Tony, Can you please push this? > > This needs to get merged via linux-mmc list. > Sure. We will repost it. Regards, Madhu > Regards, > > Tony