pastebin (don't paste here) the output of the end of 'dmesg' when you plug the AMU in
also 2 cgminer outputs:
1) cgminer -n
2) cgminer -D -T -verbose ... your options ... 2> debug.log
and let that run for about 30 seconds - and pastebin it or upload the log somewhere
I don't have a powered hub, I guess I better get one to see what's happening myself
(tried to get one last week and oddly none of the shops I went to had one ... except one that was crap)
One other thing to try is to leave it unplugged for about a minute then see if that fixes it
I had mine go into a weird state not being recognised after using different OSs and being left unplugged for a while fixed it for me
The error I got when this happened in the debug log was an error 4 setting the baud
I might try see if that is reproduceable - the error and the unplug fix, and if so, when it happens print a message to do that.
Here you go:
http://pastebin.com/tRWSfvNVI hope it helps. I would be happy to provide more info, if needed.
Leaving it unplugged for a minute had no effect.
Hmm yep you are getting the same error in there that I have got twice (once on windows and once on linux)
and I managed to clear it somehow ...
[2013-05-31 22:13:28] AMU: cgid 0 SetBaud got err 4
Now to work out how I cleared it ...