vt/vga: ignore ACPI_FADT_NO_VGA unless running virtualized

[royger]

Summary

There's too many broken hardware out there that wrongly has the
ACPI_FADT_NO_VGA bit set. Ignore it unless running as a virtualized
guest, as then the expectation would be that the hypervisor does
provide correct ACPI tables.

Sponsored by: Citrix Systems R&D
PR: 230172

[emaste]

sys/dev/vt/hw/vga/vt_vga.c

1267

Some other cases in the tree seem to add (not actually necessary) parens

ignore = (vm_guest == VM_GUEST_NO);

to me this is a bit clearer.

[emaste]

Also let's MFC this to include in 13.1

[emaste]

We should update vt.4 also

hw.vga.acpi_ignore_no_vga
        Set to 1 to force the usage of the VGA driver regardless of
        whether ACPI IAPC_BOOT_ARCH signals no VGA support.  Can be used
        to workaround firmware bugs in the ACPI tables.

[royger]

Update vt man page.

[eugen_grosbein.net]

Please merge it to stable/12, too.

[0mp]

The manual page change seems OK.

share/man/man4/vt.4

209 ↗

(On Diff #103938)

Please bump the Dd of the manual page when committing.