Comment 1 for bug 506681

I've just experienced the problem as well. Upon further analysis, it turns out that for me gpg-agent is started by the session startup scripts like this:

/usr/bin/gpg-agent --daemon --sh --write-env-file=/home/siretart/.gnupg/gpg-agent-info-faui44a /usr/bin/dbus-launch --exit-with-session /usr/bin/seahorse-agent --execute gnome-session

you can see this from the output of 'ps aux | grep gpg-agent'

this means that the startup script make gpg-agent start seahorse, which interferes badly with smartcards, see bug #185563