Date: Wed, 03 Feb 2010 16:53:12 +0200 From: Andriy Gapon <avg@icyb.net.ua> To: freebsd-acpi@FreeBSD.org Cc: Rui Paulo <rpaulo@FreeBSD.org>, John Baldwin <jhb@FreeBSD.org> Subject: acpi_cpu: _PDC vs _OSC Message-ID: <4B698DD8.4010404@icyb.net.ua>
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What do you think about changing logic of evaluating _PDC and _OSC for Processor object in acpi_cpu_attach? It seems that later versions of ACPI standard deprecate _PDC in favor of _OSC. Although, in practice they seem to be present or not present together, sometimes _PDC being only a wrappper around _OSC. There are still, of course, systems with only _PDC present. I assume that there are systems with only _OSC too. I would like to change the order, so that _OSC evaluation is attempted first and only if it fails then proceed with _PDC. Also, I would like to print status returned by _OSC (in case of successful evaluation) if it is not zero. (Note: this is not the same as status of evaluating _OSC). And I am going to fix the following comment: * On some systems we need to evaluate _OSC so that the ASL * loads the _PSS and/or _PDC methods at runtime. Although on many systems either _PDC or _OSC or both dynamically load SSDTs that contain additional Processor objects like _PSS and _PCT, I haven't seen any system where _OSC would load _PDC. And, honestly, that wouldn't make any sense. Perhaps, comment's author meant _PCT in place of _PDC, or something like that. Please let me know what you think. Thanks! Convenience link: http://download.intel.com/technology/IAPC/acpi/downloads/30222305.pdf -- Andriy Gapon
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