From: "Stephen Schwarm, CSDP" <w3eve@earthlink.net>
To: "linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>
Subject: simple sd card performance bug fix on OMAP
Date: Fri, 28 May 2010 15:05:00 -0400 [thread overview]
Message-ID: <4C0013DC.6060601@earthlink.net> (raw)
[-- Attachment #1: Type: text/plain, Size: 922 bytes --]
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.
Steve Schwarm
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next reply other threads:[~2010-05-28 19:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-28 19:05 Stephen Schwarm, CSDP [this message]
2010-05-28 19:53 ` simple sd card performance bug fix on OMAP Madhusudhan
2010-05-28 19:54 ` Gadiyar, Anand
2010-06-02 17:18 ` Madhusudhan
2010-06-10 6:36 ` Tony Lindgren
2010-06-10 15:31 ` Madhusudhan
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