svn commit: r297954 - in head/sys: boot/efi/loader/arch/amd64 boot/i386/libi386 x86/acpica

[Andrew Turner]

On Thu, 14 Apr 2016 04:59:51 +0000 (UTC)
Warner Losh <imp at FreeBSD.org> wrote:

> Author: imp
> Date: Thu Apr 14 04:59:51 2016
> New Revision: 297954
> URL: https://svnweb.freebsd.org/changeset/base/297954
> 
> Log:
>   Deprecate using hints.acpi.0.rsdp to communicate the RSDP to the
>   system. This uses the hints mechnanism. This mostly works today
>   because when there's no static hints (the default), this value can
> be fetched from the hint. When there is a static hints file, the hint
>   passed from the boot loader to the kernel is ignored, but for the
> BIOS case we're able to find it anyway. However, with UEFI, the
> fallback doesn't work, so we get a panic instead.
>   
>   Switch to acpi.rsdp and use TUNABLE_ULONG_FETCH instead. Continue to
>   generate the old values to allow for transitions. In addition, fall
>   back to the old method if the new method isn't present.
>   
>   Add comments about all this.
>   
>   Differential Revision: https://reviews.freebsd.org/D5866

Why not pass it in using module data as we do with the DTB? It would
fix issues where we have either or both static hints and a stat env.

Whatever method is decided we will also need it on arm64 as we claim to
support ACPI there, although no backwards compatibility will be needed
as the code is most likely broken as it's only partially been tested.

Andrew