I had several old ssh keys in my
~/.gnupg/sshcontrol so I removed all lines in this file and rebooted my computer. Now, I can't add ssh keys to gpg agent anymore:
$ cat ~/.gnupg/gpg-agent.conf enable-ssh-support $ gpg-connect-agent --verbose /bye gpg-connect-agent: closing connection to agent $ gpg-connect-agent updatestartuptty /bye OK $ ssh-add -l The agent has no identities. $ ssh-add ~/.ssh/id_rsa Enter passphrase for /home/cassou/.ssh/id_rsa: Identity added: /home/cassou/.ssh/id_rsa (/home/cassou/.ssh/id_rsa) $ ssh-add -l The agent has no identities.