Li, Aubrey wrote:
> On Friday, August 10, 2007 10:55 AM, Dana.Myers at Sun.COM wrote:
> 
>> Li, Aubrey wrote:
>>> On Friday, August 10, 2007 4:42 AM, Dana.Myers at Sun.COM wrote:
>>>
>>>> Aubrey wrote:
>>>>
>>>>> For P-state driver, I have one suggestion. There are still some old
>>>>> machines which support early ACPI specs but not support P-state.
>>>>> We should not ignore this kind of machine. So IMHO P-state driver
>>>>> should check the version of ACPI and doesn't make unnecessary
>>>>> warning.
>>>> It's a bit difficult to tell what version of ACPI a BIOS has been
>>>> "written for"; there's no version stamp on a BIOS saying "compliant
>>>> with ACPI version x.xx".  Certainly we shouldn't generate warnings
>>>> when a feature simply isn't supported, though.
>>> Well, there is a structure member "Revision" in the RSDP structure.
>>> The ACPI version 1.0 revision number of this table is zero. Later
>>> the value for this field is 2. That's enough for PSS object
>>> checking. I'll come up with a patch against it if it's acceptable.
>> That field is the revision of the RSDP structure itself, not
>> of the ACPI
>> tables.
>> It's been '2' in both the ACPI 2.x and 3.x specs and '0' in
>> the 1.x spec,
>> so I suppose we could infer from it that a BIOS written in the
>> pre-2.0 era is present,  but I'm afraid I don't understand the exact
>> error 
>> case we're
>> discussing in the first place.  What is the problem we're
>> trying to solve?
>> I'd prefer to solve the root-cause of the problem rather use the RSDP
>> structure version in a way not intended by the spec.
>>
> 
> I think it's PSS object not found. I checked ACPI spec and found PSS
> object is introduced since ACPI2.0.

Right. In cpu_acpi.c we try to evaluate the _PSS object and 
AcpiEvaluateObjectTyped() fails to evaluate it because the _PSS is not 
there. This results in a call to cmn_err(). As I said previously, this 
messages is being displayed on the console. A bug was filed against this 
a couple of days ago:

6589662 Error messages from cpu_acpi on install boot w/snv_70

I'm changing the behavior so that the message only gets logged to the 
system log. I'm not sure that I see a reason for checking the version 
and I'm not if there is a reliable way to do this. I didn't believe that 
it was the case that a BIOS implemented a specific ACPI version.

Regardless, we're going to want to log a message saying that we can't 
manage the P-states because we don't have a _PSS object (for whatever 
reason).

> So the machine wih ACPI1.0 don't have this object.
> IMHO, that means speedstep driver would only work on the machines with
> ACPI2.0 and later.
> So, for those ACPI1.0 machine, PSS warning message is not necessary.
> But I need some time to verify the root cause.
> 
>>>> What version did you find on the Intel website?  We're
>>>> currently at 20060721 in Solaris Nevada.
>>>>
>>>> Dana
>>> The current version is 20061109, here is the changelog.
>>> http://www.intel.com/technology/iapc/acpi/downloads/changes.txt
>>> I'm new to solaris, just want to know when and how this package is
>>> updated into solaris.
>> Thanks; we currently have a later source drop in-house, but there's
>> an issue in 20070508 and later which results in a dead-lock when
>> delivering GPE events.
>> Do you know when Bob Moore will be back from sabbatical?
> 
> Sorry, I have no idea, ;-)
> 
> Best Regards,
> -Aubrey
> Intel OpenSolaris Team
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