Date: Thu, 4 Feb 2010 16:57:52 -0500 From: John Baldwin <jhb@freebsd.org> To: Andriy Gapon <avg@icyb.net.ua> Cc: freebsd-acpi@freebsd.org Subject: Re: acpi_cpu: _PDC vs _OSC Message-ID: <201002041657.52232.jhb@freebsd.org> In-Reply-To: <4B6B2337.8070404@icyb.net.ua> References: <4B698DD8.4010404@icyb.net.ua> <4B69E0BA.4080104@root.org> <4B6B2337.8070404@icyb.net.ua>
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On Thursday 04 February 2010 2:42:47 pm Andriy Gapon wrote:
>
> Below is the patch that I have.
> _PDC is evaluated only if _OSC evaluation fails.
> _OSC status returned by AML is reported if not zero.
> Small changes in comments.
>
> BTW, 'if (sc->cpu_features)' check could probably be dropped, because we
> initialize cpu_features with non-zero value and then only bit-or to it.
>
> Index: sys/dev/acpica/acpi_cpu.c
> ===================================================================
> --- sys/dev/acpica/acpi_cpu.c (revision 203497)
> +++ sys/dev/acpica/acpi_cpu.c (working copy)
> @@ -345,26 +345,13 @@
> }
>
> /*
> - * CPU capabilities are specified as a buffer of 32-bit integers:
> - * revision, count, and one or more capabilities. The revision of
> - * "1" is not specified anywhere but seems to match Linux.
> + * CPU capabilities are specified in
> + * Intel Processor Vendor-Specific ACPI Interface Specification.
> */
> if (sc->cpu_features) {
> - arglist.Pointer = arg;
> - arglist.Count = 1;
> - arg[0].Type = ACPI_TYPE_BUFFER;
> - arg[0].Buffer.Length = sizeof(cap_set);
> - arg[0].Buffer.Pointer = (uint8_t *)cap_set;
> - cap_set[0] = 1; /* revision */
> - cap_set[1] = 1; /* number of capabilities integers */
> - cap_set[2] = sc->cpu_features;
> - AcpiEvaluateObject(sc->cpu_handle, "_PDC", &arglist, NULL);
> -
> /*
> - * On some systems we need to evaluate _OSC so that the ASL
> - * loads the _PSS and/or _PDC methods at runtime.
> - *
> - * 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.
--
John Baldwin
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