RE: RE: ACPI -- Workaround for broken DSDT

[Nate Lawson <nate-Y6VGUYTwhu0@public.gmane.org>]

On Wed, 4 Feb 2004, Scott T. Smith wrote:
> On Wed, 2004-02-04 at 21:15, Brown, Len wrote:
> > Windows doesn't have to do anything.  By being first to ship ACPI, that
> > implementation provided the defacto ACPI compliance test to which all
> > BIOS' are tested -- even if that implementation is not ACPI spec
> > compliant.  No, only under dire circumstances will we emulate Windows
> > bugs in Linux.
>
> So basically we shouldn't use ACPI then, and instead use APM?
>
> If Linux ACPI could emulate the bugs that Windows has, then ACPI would
> work on Linux on most platforms right away.  That would make Linux more
> accessible to people.  Linux already has a bunch of hacks to support
> broken hardware which presumably Windows can work around; this seems to
> be just another one of those.

We're doing something slightly different with ACPI on FreeBSD.  We add
hacks^Wworkarounds for buggy DSDT whenever possible but they are under a
kernel option, #ifndef ACPICA_PEDANTIC.  The default is for this option to
give maximum compatibility with the stock DSDT, at the expense of spec
correctness.  However, by adding that option and compiling a kernel, OEMs
could test against ACPI-CA as a reference implementation while ordinary
users get maximum compatibility.

I think the ACPI-CA developers should take a similar tact.  Len, who is on
the Linux side, could suggest distribution maintainers use the option that
gives maximum Windows compatibility when shipping a distro.  Bob, who is
on the ACPI-CA side, could encourage OEMs to test with the option
disabled.  It might even make sense for a Linux distro maintainer to
partner with ACPI-CA to provide a reference ISO that OEMs could boot that
had a /sbin/init that tests the various APIs for correctness.  Both Andy
and I thought this was a good direction to go and perhaps people are
already making progress in that area.

-Nate


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