From owner-freebsd-mobile@FreeBSD.ORG Fri Jun 21 01:02:15 2013 Return-Path: Delivered-To: freebsd-mobile@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 79D4E986; Fri, 21 Jun 2013 01:02:15 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-qc0-x230.google.com (mail-qc0-x230.google.com [IPv6:2607:f8b0:400d:c01::230]) by mx1.freebsd.org (Postfix) with ESMTP id 1F1C71FFF; Fri, 21 Jun 2013 01:02:15 +0000 (UTC) Received: by mail-qc0-f176.google.com with SMTP id z10so4127140qcx.21 for ; Thu, 20 Jun 2013 18:02:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type; bh=K1zWoeLapUKqt4bn3FQ8YSdpKZYRowEtIFIzzZGmT18=; b=DOhmpT1Wky70TVJKFSO920d432oBGi2venNh06oCY1HxA3MQMfJkAJlyEojVO7KByi CRN6ioYVKg2x6/4n5Dc8HMb+GL0KrWD3GYE3+PUfTM1ohPZi1m4+CfUV8c/qMqKL9vER lJaVLjdPXqzwlqYabI54zz8/Gf4NlaZXKTihGQMYC5g0fXOc89RWODudYAcFnq7hDkmZ PzazWG3rdGOIb/m8vNezUtTaFgZ5qdxNNLTs7tJlfj7ZkwgJDMh+bZ8CXYHp/eduxb3z nrgd/aqLZQPPu5BrkInhepJciqAKVPZklPayCc7eSGo4i6268IH3nnnhGPFkfeV0PnEg /0pg== MIME-Version: 1.0 X-Received: by 10.49.98.196 with SMTP id ek4mr12149460qeb.8.1371776534646; Thu, 20 Jun 2013 18:02:14 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.224.5.65 with HTTP; Thu, 20 Jun 2013 18:02:14 -0700 (PDT) In-Reply-To: References: Date: Thu, 20 Jun 2013 18:02:14 -0700 X-Google-Sender-Auth: -CONjKYYXZqn2WjOusEeUZh6mrg Message-ID: Subject: Re: Atom N450 + C3 + HPET == bad timer behaviour From: Adrian Chadd To: freebsd-mobile@freebsd.org, freebsd-current , Alexander Motin Content-Type: text/plain; charset=ISO-8859-1 X-BeenThere: freebsd-mobile@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Mobile computing with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 21 Jun 2013 01:02:15 -0000 On 20 June 2013 16:45, Adrian Chadd wrote: > Hi, > > I'm having issues with HPET + C3 state on this Atom N450 based > netbook. This is (shocking, I know!) running -HEAD (r251605.) > > If I use C2, HPET is fine. > > If I use RTC, i8254, LAPIC, C3 is also fine. > > But C3 + HPET results in multi-second pauses where it should be 1 second. > > I've disabled powerd and verified that dev.cpu.0.freq=1667; so it's > not CPU frequency related. > > Doug found this: apparently SMI + timer fondling doesn't quite work out? > > http://lkml.indiana.edu/hypermail/linux/kernel/1102.3/00842.html .. and the resolution: http://lkml.indiana.edu/hypermail/linux/kernel/1102.3/00957.html "clockevents: Prevent oneshot mode when broadcast device is periodic When the per cpu timer is marked CLOCK_EVT_FEAT_C3STOP, then we only can switch into oneshot mode, when the backup broadcast device supports oneshot mode as well. Otherwise we would try to switch the broadcast device into an unsupported mode unconditionally. This went unnoticed so far as the current available broadcast devices support oneshot mode. Seth unearthed this problem while debugging and working around an hpet related BIOS wreckage. Add the necessary check to tick_is_oneshot_available()." does that help? adrian