Date: Fri, 22 Jun 2012 10:30:25 +0300 From: Andriy Gapon <avg@FreeBSD.org> To: Sean Bruno <seanbru@yahoo-inc.com> Cc: "sbruno@freebsd.org" <sbruno@FreeBSD.org>, "freebsd-acpi@freebsd.org" <freebsd-acpi@FreeBSD.org> Subject: Re: [CFT] Sparse Cstate Support -- Its possible, that I don't know what I'm doing. Message-ID: <4FE41F11.4080601@FreeBSD.org> In-Reply-To: <1340225679.2858.26.camel@powernoodle.corp.yahoo.com> References: <1340121728.5203.8.camel@powernoodle> <4FE0EA24.6000906@FreeBSD.org> <1340142162.3201.12.camel@powernoodle.corp.yahoo.com> <4FE158FF.5070209@FreeBSD.org> <1340208849.2858.2.camel@powernoodle.corp.yahoo.com> <4FE23004.3080609@FreeBSD.org> <1340225679.2858.26.camel@powernoodle.corp.yahoo.com>
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on 20/06/2012 23:54 Sean Bruno said the following: > On Wed, 2012-06-20 at 13:18 -0700, Andriy Gapon wrote: >>> I also, disagree with the idea of "FreeBSD C-states" as that is not >> the >>> intention of the code. The code, from my read, is trying to >> interpret >>> C-states as though they are always defined sequentially and >> non-sparse. >> >> I seem to recall that this is an ACPI requirement. I could be >> mistaken, but no >> time to double-check at the moment. >> >> > > Just to check as I'm actively looking at this code I went and grabbed > the December 6, 2011 ACPI spec. http://www.acpi.info/spec.htm > > chap 8.1 pretty clearly states that C2 and C3 are optional states. So it > appears that you can have a C3 without a C2. So, I suspect that the > idea that the index the cx_states array is always going to be 1 less > that the ACPI Cstate value isn't by spec. Or something ... :-) I think that the chapter on _CST is more relevant here (8.4.2.1 in my copy of the spec). But anyway, there is no such requirement in the specification. I was misremembering the requirement that states should be ordered. So, would you like to produce a cleaned up version of your patch with only this change in it? -- Andriy Gapon
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