Date: Mon, 13 Mar 2006 09:03:35 -0800 From: Nate Lawson <nate@root.org> To: Kris Kennaway <kris@obsecurity.org> Cc: stable@FreeBSD.org Subject: Re: Problems with hw.acpi.cpu.cx_lowest=C2 (Re: cvs commit: src/etc/defaults rc.conf) Message-ID: <4415A5E7.8000801@root.org> In-Reply-To: <20060313083954.GA46731@xor.obsecurity.org> References: <200601290551.k0T5pwEC028440@repoman.freebsd.org> <20060129060654.GA47495@xor.obsecurity.org> <20060129061300.GA47596@xor.obsecurity.org> <43DC5E0B.40003@root.org> <20060129063007.GA47800@xor.obsecurity.org> <20060313083954.GA46731@xor.obsecurity.org>
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Kris Kennaway wrote: > On Sun, Jan 29, 2006 at 01:30:07AM -0500, Kris Kennaway wrote: >> On Sat, Jan 28, 2006 at 10:17:47PM -0800, Nate Lawson wrote: >>> Kris Kennaway wrote: >>>> On Sun, Jan 29, 2006 at 01:06:54AM -0500, Kris Kennaway wrote: >>>> >>>>> On Sun, Jan 29, 2006 at 05:51:58AM +0000, Nate Lawson wrote: >>>>> >>>>>> njl 2006-01-29 05:51:58 UTC >>>>>> >>>>>> FreeBSD src repository >>>>>> >>>>>> Modified files: >>>>>> etc/defaults rc.conf >>>>>> Log: >>>>>> Enable the lowest Cx state by default. This will save power and we have >>>>>> had enough testing of acpi_cpu to know this is stable now. >>>>> On my desktop system (running RELENG_6 though), setting >>>>> hw.acpi.cpu.cx_lowest=C0 causes atrocious performance. Is it broken >>>>> in 6.x? >>>> C2, sorry. >>> Ah, C0 should be disallowed already I thought (try it). >>> >>> As for C2, I MFCd a patch to acpi_cpu.c in November that should prevent >>> this (1.57.2.1). Do you get a printf on console? >> This might be it: turns out I never rebooted to the newer kernel I >> built earlier this month, and I am still running a kernel from Nov 6. >> I'll get back to you. > > I finally managed to test this in RELENG_6. The system performance is > not obviously bad, but sound playback is distorted (e.g. the 'bell' in > KDE is much higher pitched than it should be, and on the console it is > low pitched and lasting about 3 seconds). Nothing is logged on > console. > > There may be other problems that I didn't notice right away, but the > sound problems were enough to make me turn it off again. Are you sure that's the cause? (Does setting cx_lowest to C1 fix it?) Can you send the output of sysctl hw.acpi so we can see how often each cx type is being run? -- Nate
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