All of lore.kernel.org
 help / color / mirror / Atom feed
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



[-- Attachment #2: w3eve.vcf --]
[-- Type: text/x-vcard, Size: 227 bytes --]

begin:vcard
fn:Stephen  Schwarm, CSDP
n:Schwarm, CSDP;Stephen 
adr;dom:;;30 Hayden Woods;Wrentham;MA;02093
email;internet:schwarm@ieee.org
tel;home:508-384-7697
tel;cell:508-922-9688
x-mozilla-html:FALSE
version:2.1
end:vcard


             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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4C0013DC.6060601@earthlink.net \
    --to=w3eve@earthlink.net \
    --cc=linux-omap@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.