Date: Thu, 19 Feb 2009 20:01:56 +0200 From: Andriy Gapon <avg@freebsd.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r188814 - head/sys/dev/acpica Message-ID: <499D9E94.1090309@freebsd.org> In-Reply-To: <200902191439.n1JEdqRM099733@svn.freebsd.org> References: <200902191439.n1JEdqRM099733@svn.freebsd.org>
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on 19/02/2009 16:39 Andriy Gapon said the following: > Author: avg > Date: Thu Feb 19 14:39:52 2009 > New Revision: 188814 > URL: http://svn.freebsd.org/changeset/base/188814 > > Log: > acpi_cpu: fixup for PIIX4E PCI config related to C2 > > This is triggered only if BIOS configures ACPI_BITREG_BUS_MASTER_RLD > aka BRLD_EN_BM to 1. > Rationale: > 1. we do not support C3 on PIIX4E > 2. bus master activity need not break out of C2 state > 3. because of CPU_QUIRK_NO_BM_CTRL quirk we may reset bus master here should have been "never" --------------------^^^ > status which would result in immediate break out from C2 > > So if you have seen > cpu0: too many short sleeps, backing off to C1 > with this chipset before you may want to try cx_lowest of C2 again. -- Andriy Gapon
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