Applied to 2.4, too.

I'll create a branch for this work. Then, I'll incorporate changes to master.

OK. I pushed: rG227b3b14f4be: tests:tpm2dtests: Modify tests with SWTPM and relax the condition.
... which doesn't require swtpm_ioctl and tssstartup any more.

I pushed rG321f9c0a3f28: tests:tpm2dtests: Fix tests with TPM2D. and rG98dd6f7af6aa: tests:tpm2dtests: Fix tests with SWTPM. (and other small changes).
Now, it works with two cases:

• tpm_server
• swtpm, swtpm_ioctl, and tssstartup

In 2.2, KEYINFO output doesn't support A-flag for the information if card is online or not.
We need to clean up this discrepancy.

I pushed rGff42ed0d69bb: gpg: Enhance agent_probe_secret_key to return bigger value. to fix this issue.

Backported to 2.2 branch.

Firstly, I clean up the code with each individual thread for monitoring something; That's T6692 and T6693.
Then, I pushed rG76a2f180286e: agent: Better interaction between main loop and cache expiration. and rG92de0387f04b: agent: Introduce management of timer to expire cache entries.
No more use of tick, but timers.

Other problems of yat2m transformation:
https://bugs.debian.org/1050886

It's pushed by rG716e59b0b628: agent: Add agent_kick_the_loop function.

Pushed the change by rG7025375e8bec: agent: Have a thread monitoring parent PID and homedir.
It depends on T6682 to wake up the loop.

Push the code by rG95186ae92f92: agent: Use a thread to monitor socket takeover.

I concluded that it's just simpler not to do so. Since expected use cases are only for passphrase cache expiration and some monitoring something, it would be overkill.

I confirmed that the pselect EINTR problem of Linux (at least for x86) has not yet been fixed: https://lkml.org/lkml/2018/3/21/909

I found a troff reference: https://www.quut.com/berlin/ms/troff.html

Ideally, we should change the source document to use @minus{} for a minus sign, and keep - only when it means a hyphen. But we cannot do that blindly; We need to handle it with care, in a way of case by case (Texinfo manual suggests no use of @minus{} with @code or @example, but it is needed for groff man pages in many cases).... We would need to consider each occurrence of - in our document. That's too much (if it were me to fix).

Using Ubuntu, it's GnuPG 2.2 (which doesn't have the fix of T4585). Without the fix, killing gpg (by CTRL-C) causes problematic situation where pinentry remains asking.
That's because gpg-agent and pinentry don't know the frontend side has been killed. T4585 introduced a watching thread into gpg-agent, so that it can correctly detect lost of frontend.