From: "Madhusudhan" <madhu.cr@ti.com>
To: "'Stephen Schwarm, CSDP'" <w3eve@earthlink.net>,
linux-omap@vger.kernel.org
Subject: RE: simple sd card performance bug fix on OMAP
Date: Fri, 28 May 2010 14:53:02 -0500 [thread overview]
Message-ID: <006801cafe9f$6209e030$544ff780@am.dhcp.ti.com> (raw)
In-Reply-To: <4C0013DC.6060601@earthlink.net>
> -----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
>
next prev parent reply other threads:[~2010-05-28 19:53 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-28 19:05 simple sd card performance bug fix on OMAP Stephen Schwarm, CSDP
2010-05-28 19:53 ` Madhusudhan [this message]
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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