strange problem with Intenso 4GB SDHC card

Doug Jones dj6mf at
Thu Jul 24 01:21:57 CEST 2008

Stefan Fröbe wrote:
> Thanks for the link, seems to be quite valuable to me as it explains the 
> background quite well!
>     Something similar has been happening with SD cards on the OLPC laptop
>     (another example of hardware specifically designed for the FOSS world)
>     for at least the last six months.  Last time I checked, there was still
>     no real fix.  
> Well, from recent comments it looks like a 400ms delay (yuck!) in
> drivers/mmc/core/sd.c is a temporary workaround, but the root cause (as 
> Andy already suggested) seems to be related to the resume cycle.
>     Has been a major pain for people who want to multiboot  --
>      forces them to use storage devices that don't fit inside the case.
> At least it doesn't look like a HW issue with the card, then.
> Stefan

Just spent some time looking at that bug ticket again.  I've been trying 
to follow this story ever since my OLPC trashed the partition table on 
my 16GB SDHC card back in January.

A consensus seems to be building that suspend/resume is involved.  But I 
don't think anybody really understands what's going on, and people have 
been bashing their heads against this again and again for six months.

If something like this is happening in the Neo, then this could turn 
into a world of hurt.


Everybody, get a Micro-SD card and stick it in your Neo.  Put some 
random files on it, you don't have to do anything serious with it, just 
let it sit in there for a while.  Periodically check that you can still 
see those files.  If you lose those files, post about it.  Maybe we 
should start a new thread to keep track of this data.

There have been some indications that partition type may have some 
effect on this problem on the OLPC.  So, shrink the default vfat 
partition that came on the card and put an ext3 on there too.  If you 
want to be adventurous, try some other types.

If more people start seeing problems like this, we ought to start 
comparing notes with the OLPC people who are working on this.  And 
Pierre Ossman too, he did a lot of work on SD support in the kernel.

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