From owner-freebsd-acpi@FreeBSD.ORG Wed May 7 18:34:41 2014 Return-Path: Delivered-To: freebsd-acpi@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 3E540EB0; Wed, 7 May 2014 18:34:41 +0000 (UTC) Received: from bigwig.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 14388C9E; Wed, 7 May 2014 18:34:41 +0000 (UTC) Received: from jhbbsd.localnet (unknown [209.249.190.124]) by bigwig.baldwin.cx (Postfix) with ESMTPSA id EE815B964; Wed, 7 May 2014 14:34:39 -0400 (EDT) From: John Baldwin To: Ian Lepore Subject: Re: proposal: set default lid state to S3, performance/economy Cx states to Cmax Date: Wed, 7 May 2014 12:26:34 -0400 User-Agent: KMail/1.13.5 (FreeBSD/8.4-CBSD-20140415; KDE/4.5.5; amd64; ; ) References: <201405061637.30037.jhb@freebsd.org> <1399414546.22079.286.camel@revolution.hippie.lan> In-Reply-To: <1399414546.22079.286.camel@revolution.hippie.lan> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201405071226.34487.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.2.7 (bigwig.baldwin.cx); Wed, 07 May 2014 14:34:40 -0400 (EDT) Cc: Kevin Oberman , "freebsd-acpi@freebsd.org" , "freebsd-arch@freebsd.org" X-BeenThere: freebsd-acpi@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: ACPI and power management development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 07 May 2014 18:34:41 -0000 On Tuesday, May 06, 2014 6:15:46 pm Ian Lepore wrote: > On Tue, 2014-05-06 at 16:37 -0400, John Baldwin wrote: > > On Tuesday, May 06, 2014 2:08:35 pm Adrian Chadd wrote: > > > On 5 May 2014 13:57, John Baldwin wrote: > > > > > > > The user in question found this on 9-stable with the existing defaults as the > > > > HPET was just plain broken on their system and that was unrelated to Cx states. > > > > (Rather, Cx states were only involved because worries about them are why the > > > > system chose to use HPET. Had Cx states been enabled by default, they would > > > > have had to disable those as well in addition to forcing LAPIC instead of > > > > HPET.) > > > > > > Hm. Sounds uncomfortable. How does Windows run on systems like this? > > > Do the windows drivers just disable HPET and use LAPIC or worse for > > > timing, and just ignore anything lower than C1? > > > > I have no idea. Maybe they use the RTC. :-/ Maybe the HPET on these systems > > works if you use it "sparingly". I believe OS X might have only used the HPET > > to provide the "missing" LAPIC wakeups when entering Cx for example. (Our current > > eventtimer system wants to always use whichever timer it picks, not switch off > > between them.) > > > > The eventtimer code is happy to switch between timers on the fly, but > iirc the only interface to that feature is sysctl. I found it fairly > easy to add an in-kernel API for changing the frequency of the current > timer on the fly. I think it would be just as easy to add a kernel > call to change timers as well. Ah. Well, if it's only a small slice of time where machines need this, I'd be fine with those machines just having to disable C1E and forcing use of LAPIC rather than adding a lot of goop to do LAPIC + HPET and then hoping the HPET works well enough. -- John Baldwin