Re: [Acpi] acpi questions (fwd)

From: Garst R. Reese (
Date: Thu Aug 03 2000 - 12:57:02 EST

"Grover, Andrew" wrote:
> > From: Garst R. Reese <>
> > 1. What do these error messages mean?
> > in /var/adm/debug
> > This is on an IBM Thinkpad 380D
> > Aug 1 22:03:12 aar acpid: ACPI Subsystem version [Jun 1 2000]
> > Aug 1 22:03:12 aar acpid: tbutils-0240:
> > Aug 1 22:03:12 aar acpid: *** Error: Invalid ACPI table checksum
> > Aug 1 22:03:12 aar acpid: nsapinam-0058:
> > Aug 1 22:03:12 aar acpid: DSDT is not in memory
> > Aug 1 22:03:12 aar acpid: OsdBreakpoint: Fatal error encountered
> It means the acpi subsystem was unable to load the tables, apparently due to
> an invalid checksum.

> > 2. from pm.txt
> > "If a working ACPI implementation is found, the
> > ACPI driver will override and disable APM, otherwise the APM driver
> > will be used."
> > What is meant here by -working-
> There are a number of tables that the bios provides, which the ACPI
> subsystem consumes. These tables have to be laid out properly (checksums
> work out, no illegal grammar, etc.) for ACPI to work. It looks like what may
> be happening in your case is that your system has some ACPI support (or we
> wouldn't be finding any tables) but that they're not correctly formatted.
> Just a guess. Does IBM have any bios updates for that machine?

It is a pre-flash machine, IBM 380XD, PIIX4, mobile pentium.
The other tables are present.

> > 3. Does anybody have acpi working to their advantage?
> Yep. But, please realize that all the features of ACPI are not fully
> implemented yet, i.e. it's still under active development.
> > 4. What does DSDT stand for?
> Differentiated System Description Table. This is where the motherboard's
> resources are described, in Acpi Machine Language (AML).

Is there a way to build a correct substitute? The motherboard's
resources are
If not, then I think it is a bug to treat acpi as working on this
machine, and it should have reverted to apm.

> > 5. Do any of the above error msgs make sense to anybody.
> Yep ;-) The interpreter currently in the kernel releases has had most of the
> debug output removed, but the plans are to have a patch which reincorporates
> these, for debugging.

I did not activate the interpreter because 120k seemed a bit much.

> > 6. Is there any *real* advantage to acpi vs apm?
> Basically, APM is bad because the bios is in charge of power management, but
> the OS is the one in the system which really has the best idea of what to
> do. So, ACPI moves PM into the OS, but still relies on the bios for the
> platform specific tables. It's still dependent on the platform bios, but not
> as much.
> IA64 also requires ACPI support.

That answers the question I did not ask for fear of sounding like a
Q. Why did ACPI go in so late in 2.3?
A. for IA64

> > 7. Has it been implemented in *any* drivers?
> I don't think so. That's a big job that's coming up.
> Regards -- Andy
Thanks for the great response.

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