pinetry and emacs

[Phillip Susi]

I have installed the pinetry module and run M-x pinentry-start, as well
as added allow-emacs-pinentry to ~/.gnupg/gpg-agent.conf, yet whenever I
try signing an email in mu4e, pinentry gets into a fight with emacs over
the tty and everything goes all fscked up.  Why is this?  Why does
pinentry still try to take over the terminal instead of contacting
emacs?  For that matter, why can both programs fight over it?  I thoguht
only one process group was the foreground group, and only that process
group could read input from the tty.  Instead it seems like both
programs are reading some of the input and so I can't get emacs to
switch buffers, nor pinentry to enter the correct password, nor cancel.

I'm on Ubuntu 20.04 with pinentry 1.1.0 and emacs 26.3.