Amazon EC2: Disable floppy devices (fdc0, fd0,) and parallel port device (pp0)

[james.wright_digital-chaos.com]

Summary

Disable the floppy devices (fdc0, fd0) and parallel port device (ppc0) on Amazon EC2 instances. They are not present on these machines and output an error on boot (see below);

# dmesg | grep fdc
fdc0: <floppy drive controller> port 0x3f0-0x3f5,0x3f7 irq 6 drq 2 on acpi0
fdc0: does not respond
device_attach: fdc0 attach returned 6
fdc0: No FDOUT register!

# dmesg | grep ppc
ppc0: cannot reserve I/O port range

Bugzilla PR:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=233861

Test Plan

[james.wright_digital-chaos.com]

Updated file path in diff for Phabricator Diffusion browsing

[lwhsu]

@cperciva I think this patch is good, can you check it? Thanks!

[cperciva]

Which instance type are you seeing this on? I haven't been able to reproduce it.

[james.wright_digital-chaos.com]

In D18482#562033, @cperciva wrote:

Which instance type are you seeing this on? I haven't been able to reproduce it.

I think it may have been a t2.micro at the time but not 100% sure now. Everything I have is running on t3a instances now and I can't reproduce it on these types either, so I think it may have just been an issue on the older generations.

[cperciva]

Ah, on t2.micro I see warnings about fdc (but not about ppc). Normally I aim to minimize the difference between EC2 and "stock" FreeBSD, but I guess there's no harm in making this change even if it only affects older instance types.

[cperciva]

I think I must have not realized that the author of this patch wasn't a committer. Sorry James, I've committed this now!

[imp]

It would be even better to remove all of these devices from the hints entirely.
We're well past the time when they are needed as a fallback. We should move all the isa hints to isa.hints and allow people with really old, non ACPI or broken ACPI systems to load it.
Plus, in -current, all of those are gone. Only atkbdc remains (and it should go too)