Date: Fri, 05 Feb 2010 00:13:29 +0200 From: Andriy Gapon <avg@icyb.net.ua> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-acpi@freebsd.org Subject: Re: acpi_cpu: _PDC vs _OSC Message-ID: <4B6B4689.4020708@icyb.net.ua> In-Reply-To: <201002041657.52232.jhb@freebsd.org> References: <4B698DD8.4010404@icyb.net.ua> <4B69E0BA.4080104@root.org> <4B6B2337.8070404@icyb.net.ua> <201002041657.52232.jhb@freebsd.org>
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on 04/02/2010 23:57 John Baldwin said the following:
> On Thursday 04 February 2010 2:42:47 pm Andriy Gapon wrote:
>> - * TODO: evaluate failure of _OSC.
>> + * On some systems evaluation of _OSC/_PDC dynamically
>> + * loads the _PSS and other methods.
>> */
>
> I would only say _OSC here. I don't think we've seen any systems that load
> something when _PDC is invoked, only when _OSC is invoked.
Actually, I think that the way it's written should be OK.
I've seen a few DSDTs where both are present and both do the same thing.
E.g.:
Scope (\_PR.CPU0)
{
Name (HI0, Zero)
Name (HC0, Zero)
Method (_PDC, 1, NotSerialized)
{
Store (CPDC (Arg0), Local0)
GCAP (Local0)
Return (Local0)
}
Method (_OSC, 4, NotSerialized)
{
Store (COSC (Arg0, Arg1, Arg2, Arg3), Local0)
GCAP (Local0)
Return (Local0)
}
...
Looks like CPDC is "Convert _PDC" and COSC is "Convert _OSC" and GCAP is "G...
capabilities", whatever "G..." could mean.
--
Andriy Gapon
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