Smartcard reader disconnects

[Miguel Barbosa Gonçalves]

Hi!

I am using a USB Shell Token v2 that I bought from KernelConcepts with
a OpenPGP 2.1 smartcard.

Sometimes, after doing an operation, the smartcard reader apparently
disconnects and I can only get it to work if I disconnect and
reconnect it.

When it gets disconnected, if I try to access it, I get the following

$ gpg --card-status
gpg: selecting openpgp failed: ec=6.108
gpg: OpenPGP card not available: general error

By the way, I am using Ubuntu 14.04 and everything works except for this.

Does anyone have any idea?

Cheers,
Miguel