Charging USB devices with Fedora

[Ambrogio]

Il giorno dom, 21/03/2010 alle 15.37 +1030, Tim ha scritto:

> USB cables have four wires and a shield.  Two of those wires are used
> for power, two for data.  I've *NEVER* seen a cable that only has data
> wires, and it would be a seriously bad idea to attempt it.  The shield
> isn't a data ground, and shouldn't be used that way.  And there's ZERO
> way that such a cable could be used to power/charge anything.
Well,

I don't have anymore the 2 bad devices.
Says A and B those devices, now I have:

C that is very like to A. Same country (China), same case, a very
similar screen and a very similar bios. But this device has been bought
in Swiss instead of Italy. The strange (not so strange) thing is that in
swiss is sold with wall charger. The device works very well with the
wall charger, but also with the USB. The same USB that do not work for
the A and B devices.

Instead of B, I have now also in iPod shuffle.
Even if I'm unable to use it from my Linux box, I'm using itunes with
windows in a vmware virtual machine.
The iPod is seen as an USB pendrive, and if I simply umount it, I don't
obtain a charging, but if I say eject, I obtain the charging.

So, Now I'm ok.
I can't continue to analyze the problem because I don't have the bad
devices, and I don't have the right capacity to understand what appened.

Bye
 Ambrogio