problem accessing SD Card SanDisk SDSDQ-8192-E11M

[Kevin Squire]

Hi,

> I have problems accessing my 8Go SD Card

<snip>

Just to echo, I've had the same problem, and found exactly the same
thing--I can't read the card right after boot, could eventually get it
recognized, but had a hard time getting it recognized again and an
impossible time trying to boot off of it.  My card is a SDSDQ-8192 (at
least that's what I ordered--any way to verify this?).

Have you looked at dmesg after the read fails?  In my case, I found
something like:

end_request: I/O error, dev mmcblk0, sector 0
end_request: I/O error, dev mmcblk0, sector 8
end_request: I/O error, dev mmcblk0, sector 16
end_request: I/O error, dev mmcblk0, sector 24

That I could eventually read it means that it's not totally fried, but
for me at least that means that there's problems right at the
beginning of the disk, where the boot sector is.  Formatting the disk
directly (mkfs.ext2 /dev/mmcblk0) seemed to confirm this--I got "short
read" or "short write" errors for the first sector, though it
formatted the rest of the disk fine (even when fdisk had troubles
reading it).

I did try setting the clock lower, (e.g., sd_max_clk=5000000, even
2500000), but that didn't help.

For my disk, my thoughts are that the first sector is bad.  I'll try
to confirm this later today (don't have anything else available that
can read the disk right now).  The other possibility is the driver,
but right now I'm thinking that's unlikely, as others have seemed to
have gotten this disk working.  (At least it's listed at
http://wiki.openmoko.org/wiki/Supported_microSD_cards.)

Suggestions for you:

1) check dmesg after you try to access the disk
2) lower the sd_max_clk further
3) format the disk without partitioning
4) test the disk in another reader
5) ???
6) profit (maybe you can resell the disk on e-bay? ;-)

Good luck, and please post again if you find anything.

Kevin