MMC: commit dba3c29 ruins mmc card data on beagle-xm revB

T Krishnamoorthy, Balaji balajitk at
Fri Jun 22 11:33:28 EDT 2012

On Fri, Jun 22, 2012 at 5:21 PM, Paolo Pisati <p.pisati at> wrote:
> On 06/20/2012 09:23 AM, T Krishnamoorthy, Balaji wrote:
>>> i just want to say that i'm affected by this too, and i can reproduce it
>>> 100%.
>> Is it with SD or MMC card
>> Can you provide Beagle board rev info?
> kingston 4g class 4 sdhc c04g taiwan
> tested on a beagle xm rev a and rev c, both boards exhibit the same
> problem with this card, while with a brand new sandisk 16gb sdhc class 4
> card, everything is ok.
> i tried reverting dba3c29 "Enable Auto CMD12", and both cards are
> behaving fine.
>>> do you want me to run that patch or you already have enough data?
>> Can you enable MMC debug and apply the debug patch I provided.
>> The debug patch did not print any AUTOCMD errors with Ming Lei setup.
> script used for testing
> test-mmc.log: md5sum of file copied around (as you can see after the
> umount the md5 changes)
> test-mmc.syslog: mmc-debug output (plus your patch)

Thanks for testing and sharing the log.
md5sum is giving 2 different values for 8 tries which indicates writes are not
entirely random.

> after the test, my sd card was so badly wounded that it wouldn't even boot.

I guess boot partition was not updated, so I think it should boot until kernel
and fail at mounting filesystem as filesystem would have got corrupted by
previous test.

> --
> bye,
> p.

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