Bounty for fixing PR 56086: Resume hangs when tpm(4) is enabled

[coypu%sdf.org@localhost]

Hi all,

I'd normally not be offering bounties again for a while, but nia
reported having the same problem that I spent weeks blindly debugging.
"This one is personal".  Story at bottom.

I can offer $500 to a fix for PR 56086: "Resume hangs when tpm(4) is
enabled"
Hint: I suspect that the OpenBSD tpm driver does not have this problem.

(Offer expires 1/January/2023)

--

I have a Dell XPS 9550 and really wanted to fix suspend (after porting
bwfm@pci for wifi, and updating drm for graphics!), but this laptop is
cursed.
And the specific curse is that it has a TPM and the tunable to disable
it likely doesn't work.
Things I've tried to blindly debug its resume issue:
- Suspend/resume with many premutations of less drivers enabled, and
BIOS settings.
- Test every OS to see which ones suspend
- Dig through the suspend code of all the ones that successfully
suspended (Linux, OpenBSD)
- Surgically transplant the OpenBSD resume trampoline into NetBSD
(suspends on one machine, but not on the XPS)
- Try to move the memory allocations because OpenBSD decided to shift
  them to workaround a BIOS bug
- Read the ACPI docs, and any docs about resume security modes
  repeatedly.
- Attempt to transplant the entire OpenBSD tpm driver into NetBSD
- Get excited when I hear there are custom USB devices for debugging
  laptops, but fail to find ones that are expected to work for my
  laptop.
- Ask anyone I possibly can for a lead to follow.
And gradually becoming convinced that my laptop is stuck in some TPM
pre-resume check failing.

It's hard to tell how common this problem is. But I am told TPMs are
kinda common. Certainly my work laptop has one.

Thanks.