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From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Sent: Wed, June 29, 2011 5:00:15 PM
On Tue, 28 Jun 2011, Peter Rasmussen wrote:
> I used mkdosfs on the card in the following order, thus creating the attached
> output files.
> I don't know if that is what you wanted, but I hope it could enlighten the
>case.
Alan> Did you notice this response from the "mount" program?
> root@kultorvet:/home/plr# mount /dev/sda1 /mnt/usb
> mount: wrong fs type, bad option, bad superblock on /dev/sda1,
> missing codepage or helper program, or other error
> In some cases useful info is found in syslog - try
> dmesg | tail or so
Peter> Yes, I have seen it many times in the past and never really found it
useful, thus not paying much attention to it.
Peter> For instance, "dmesg|tail" doesn't add anything in this case.
Peter> In my opinion a "General Failure" message is most often a bad type of
error message. ("Who is General Failure, and why does he try to read my disk?")
Alan> Perhaps the last few lines from dmesg will indicate what's wrong. At
Peter> Yes, sometimes dmesg is useful, but just as often it isn't.
Alan> first glance it appears that your 3.0-rc4 kernel configuration is
Alan> missing something. Did you forget to build in support for VFAT
Alan> (CONFIG_VFAT_FS) or the appropriate codepage (CONFIG_NLS_ASCII and
Alan> CONFIG_NLS_CODEPAGE_437)?
Peter> Thanks a lot, now I got tracking on something! CONFIG_VFAT_FS is set, but
CONFIG_NLS_ASCII and CONFIG_NLS_CODEPAGE_437 wasn't set in my 3.0rc4 kernel.
Peter> When executing "mkfs.ext2 /dev/sda1" I could mount it, and after
rebuilding 3.0rc4 with those flags set, I can now also mount it with a FAT32 FS
on.
Peter> I didn't actually _forget_ to set the two _NLS_ flags, as I had never
made the connection unless you had mentioned it. Being from Denmark I prefer
table 865 and sometimes I have set the tables 865 and/or 850, without paying
much attention as it isn't something I have ever seen as an issue, until now.
Peter> I am however, from the 'old school' and most often build my kernels as
lean as possible, with everything that I need built in and nothing else, so they
were most often unset and not just for example set to be built as modules.
Peter> As config files sometimes changes after an update I don't always get
everything adjusted, and an ASCII or a 437 may sometimes have slipped in.
Peter> A better (=more precise) error message when attempting to mount a volume
would be great,
> Should I make another 3.0rc4 kernel with some specific config options set?
> Would it be helpful to see all my config options in my 3.0rc4 kernel? It is a
> 90KB file, so I won't just attach it unless needed.
Alan> First, check the dmesg log to see if anything obvious is wrong.
Alan> Second, compare your 3.0-rc4 with the 2.6.38 (or .39) config to see if
Alan> anything is obviously missing.
Alan>
Alan> We can go on from there.
Peter> Thanks a lot Alan, but as the two of us are in different leagues reg.
kernel issues, the word 'obvious' might be very different between us :-)
Peter> I am very glad that this first issue seems to be cleared, I learned
something, and I will continue with the next issue that I mentioned in the first
post, ie. other adapters behaving differently with the same flash card and the
same kernel.
Peter> I do hope it is more exciting than being some silly CONFIG flag.
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