Re: simple sd card performance bug fix on OMAP

[Tony Lindgren <tony@atomide.com>]

* Madhusudhan <madhu.cr@ti.com> [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.
> > 
> > <https://patchwork.kernel.org/patch/78713/>
> > 
> 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.

Regards,

Tony