SD card compatibility issue.

[Karel Gardas]

Hello,
from this group it looks like panda is really *VERY* sensitive to what
SD card you use. To clear my doubts if I dd save image correctly to SD
card I did this interesting experiment:

- dd image on Solaris 11 Express on Lenovo T500 notebook inside
internal SD card reader. I'm using ubuntu 11.04 headless image here
- move card to Freescale i.MX53 Quick Start Board and run:
sudo cmp -n 1652019200 /dev/mmcblk1 ubuntu-11.04-preinstalled-
headless-armel+omap4.img

this command should basically compare the content of image file with
the content from the beginning of the card. To my delight, the content
was the same. This means Solaris 11 Express' dd did a good job in
writing the card and the card itself is readable in i.MX53. Now move
this card to panda:
- first boot absolutely OK (even resize!)
- second boot after automatic reboot -- a lot of I/O errors
(end_request) on various sectors and such.

My conclusion: somewhere on pandaboard there is a hardware issue,
either in OMAP4 or how the board is made so that it's not compatible
with cards which are known to work in different boards/computers.

In such case I would really expect manufacturer to speak about this in
a clear words and *AT LEAST* provide a list of card they are using for
testing successfully. Since they have not done this yet I may imagine
someone in a need for pandaboard development (like me) going to shop
and spent more and more money on cards which will be useless at the
end just to find one pearl which would work in panda. This way
unfortunately panda is not looking as a cheap development solution
anymore. So list of *compatible* SD cards will help a lot in this case
IMHO!

Thanks!
Karel

[Frantisek Dufka]

On 24.6.2011 8:23, Karel Gardas wrote:
> My conclusion: somewhere on pandaboard there is a hardware issue,
> either in OMAP4 or how the board is made so that it's not compatible
> with cards which are known to work in different boards/computers.

It is quite likely it can be a software issue too. Like this one
http://www.sakoman.com/cgi-bin/gitweb.cgi?p=linux-omap-2.6.git;a=commitdiff;h=34bbeca50fcc618b43428ad65a1f62fc39fbb1dd

> So list of *compatible* SD cards will help a lot in this case

This list is hard to make since lot of manufacturers don't make their
own controllers and change parts even for same card model.

I'd guess in general Sandisk would be a safer choice than Kingston and
class 10 is not always better than class 6

See also
wiki.linaro.org/WorkingGroups/KernelConsolidation/Projects/FlashCardSurvey

It looks like most Kingston cards have lower # of open AUs for random I/O

Frantisek

[Karel Gardas]

Dobry den Frantisku,

thanks for the information. Hard to judge if software or hardware
issue. Anyway, since Sandisk was not available here I risked Transcend
Class 10 8GB (recommended as a working in another thread by another
user) and it looks like it's working fine (knocking on the wood!)

The information on Linaro website is really interesting since
following this even class 4 sandisk might be faster and better in
linux than for example class 10 kingstone. Interesting.

Also could you be so kind and repost your url to linux git commit? I'm
not able to open it at all. It shows redirection this is ok but then
the target server complains about 404 - No such project

Thanks!
Karel

On Jun 24, 9:37 am, Frantisek Dufka <duf...@gmail.com> wrote:
> On 24.6.2011 8:23, Karel Gardas wrote:
>
> > My conclusion: somewhere on pandaboard there is a hardware issue,
> > either in OMAP4 or how the board is made so that it's not compatible
> > with cards which are known to work in different boards/computers.
>

> It is quite likely it can be a software issue too. Like this onehttp://www.sakoman.com/cgi-bin/gitweb.cgi?p=linux-omap-2.6.git;a=comm...

[Gelmi]

Hello Karel,

I have also bought a Kingstone 8GB Class 10 SD card at first without
checking this topic and it does not work properly on ubuntu 11.04 (I/O
errors). Although I do not think it is the overheating problem because
ubuntu 10.10 works fine. But this is only my opinion. I would like to
check something with You, because I do not want to but another not-
working SD card. You and some other people recommend Transcend card.
Could You tell me which one do You have, this one
http://allegro.pl/transcend-karta-sdhc-8gb-class-10-fullhd-up-22mb-s-i1684497054.html
or this one http://allegro.pl/promocja-transcend-sdhc-8gb-class-10-ultimate-i1688299148.html
? I think they are the same, only the package (label stick) is
different, but still I would like to be certain.

BR,
Gelmi