RE: DDR eMMC write failures

["Subhash Jadavani" <subhashj@codeaurora.org>]

You may also try by lowering the clock speed (from 50mhz to some lower value
say 40 or 30 Mhz). See if you are still seeing the data crc errors with
lower clock speed in DDR50 mode or not.

Regards,
Subhash

> -----Original Message-----
> From: linux-mmc-owner@vger.kernel.org [mailto:linux-mmc-
> owner@vger.kernel.org] On Behalf Of Subhash Jadavani
> Sent: Sunday, November 13, 2011 10:05 PM
> To: 'Praveen Krishnan'; linux-mmc@vger.kernel.org
> Subject: RE: DDR eMMC write failures
> 
> I guess there is some issue with board level signal condition issue on
> MMC
> interface lines. You may try increasing the drive strength of interface
> lines from host controller side.
> 
> Regards,
> Subhash
> 
> > -----Original Message-----
> > From: linux-mmc-owner@vger.kernel.org [mailto:linux-mmc-
> > owner@vger.kernel.org] On Behalf Of Praveen Krishnan
> > Sent: Saturday, November 05, 2011 5:57 AM
> > To: linux-mmc@vger.kernel.org
> > Subject: Re: DDR eMMC write failures
> >
> > I am seeing some very strange things.
> >
> > When I do
> >
> > Dd if=/dev/zero of=/dev/mmcblk0 bs=512k count=200 (it fails when
> > writing about 100MB of data with a crc error)
> >
> > When I do
> > Dd if=/dev/zero of=/dev/mmcblk0 bs=64k count=3000 (it fails only
> after
> > 125 MB of data with a crc error)
> >
> > When I do
> >
> > Dd if=/dev/zero of=/dev/mmcblk0 bs=32k count=16000 (it fails when I
> > try to write 500MB of data, but good until 375MB of data)
> >
> > Any ideas what I am running into?
> >
> > Thanks,
> > Praveen
> >
> >
> > On Wed, Nov 2, 2011 at 4:51 PM, Praveen Krishnan
> <praveen.gk@gmail.com>
> > wrote:
> > > Hello all,
> > >
> > > I am working on getting the DDR50 mode up and running for the eMMC
> > > cards.  I am running into some weird CRC error cases.  Initially, I
> > > thought that everything works fine, but when I stress test it with
> > > large amounts of data (more than 100MB of writes), I notice that my
> > > console is spewed with venomous error messages.  I get a CRC error
> > and
> > > every now and then, I also see this message "Got data interrupt
> even
> > > though no data operation was in progress" and "Buffer I/O error"
> and
> > > so on.
> > >
> > > Can anybody give any pointers as to what could be causing this?
> > >
> > > Thanks a lot,
> > > Praveen
> > >
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