Problem with Raspberry Pi Compute Module

[Ronny Nilsson]

Hi Robert
I briefly had a look into what could cause this kind of problem... Revision 7 
originates from the eMMC internal firmware SW. I guess it has been updated by 
the manufacturer (Samsung) to a newer release, even though it still is sold 
as the "same old chip".

Luckily flashes is most of the time backwards compatible. It wouldn't surprise 
me if simply removing the error message would make the driver operational. 
Looking into more recent kernel versions this seems to have been done 
already. The error message has been deleted and the driver tries to continue 
anyway. Nard needs a kernel update where this (and other things) has been 
fixed. It's on my todo. Another user, Wojtek, was going to investigate this 
too a couple of days ago. Don't know how far he's come yet though. You 
could try disabling the message in drivers/mmc/core/mmc.c and see if it 
helps, otherwise I'm afraid you need to wait for the next kernel.

Regards
/Ronny


--------------------------------------------------------
> Hi,
>
> I am having trouble getting Nard to boot on my Pi CM.   I have tried two
> modules with the same MMC error.
>
> [    3.871818] mmc0: error -22 whilst initialising MMC card
> [    4.020654] mmc0: unrecognised EXT_CSD revision 7
> [    4.025529] mmc0: error -22 whilst initialising MMC card
> [    4.467877] mmc0: error -84 whilst initialising MMC card
> [    4.624657] mmc0: unrecognised EXT_CSD revision 7
> [    4.629397] mmc0: error -22 whilst initialising MMC card
>
> Has Nard been tested on the Compute Module?  Have they started using a
> newer type of eMMC?  Version7?
>
> Thanks,
> Robert Boll