+++ Paul Fidler [05-01-13 22:27 +0000]:
>
> I've just upragded from 2.425-vrs2-tcl1 to the 2.6.8.1-tcl1 kernel to see
> if it would help with my CompactFlash card woes.
>
>
> hda: SajDisk SDCFH-112, ATA DISK drive
>
> which I think should actually say:
>
> hda: SanDisk SDCFH-512, ATA DISK drive
>
> The 'n' and the '5' appear as 'j' and '1' respectively, which I suspect is
> due to a single bit error:
>
> 'n' = 0x6e = 01101110
> 'j' = 0x6a = 01101010
> ^
> '5' = 0x35 = 00110101
> '1' = 0x31 = 00110001
> ^
>
> However it's clearly not affecting every byte as (for example) 'D' is
> unaffected:
>
> 'D' = 0x44 = 01000100
> ^
> although it has the problem bit set.
The bit could well be connected to another line rather than held high or
low, so whether it goes wrong will depend on the state of other bits on the
bus (in the word).
> The problem is repeatable, and I presume it is the reason that none of the
> attempts to mount filesystems worked:
>
> FAT: invalid first entry of FAT (0xfff8 != 0xfbf8)
>
> 0xfff8 = 11111111 11111000
> 0xfbf8 = 11111011 11111000
> ^
>
> Have I got a dodgy connection somewhere on my board?
It looks very much like it. Although one would hope we would have noticed
then when comparing with other boards here. Unfortunately this problem may
well have been masked by other more general problems with the PCMCIA
subsystem not working properly. <Fx: general guilt for not spending more
time on this since you were here - I've done some work towards getting a
better base system, but it's not finished yet>
Much peering at the kernel code and the board layout might enable you to
work out which wire is likely to be at fault, but a good visual inspection
would be a good start. If you want to try another board again for
comparison, feel free.
Wookey
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