From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Feix Subject: Re: intel_idle.max_cstate=1 required on baytrail to prevent crashes Date: Fri, 18 Mar 2016 21:32:26 +0100 Message-ID: <56EC65DA.2030701@feix.cz> References: <56EA5735.1060109@feix.cz> <3870417.33uAD9HvER@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from smtp-out4.iol.cz ([194.228.2.92]:56463 "EHLO smtp-out4.iol.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756651AbcCRUci (ORCPT ); Fri, 18 Mar 2016 16:32:38 -0400 In-Reply-To: <3870417.33uAD9HvER@vostro.rjw.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" Cc: linux-pm@vger.kernel.org, Len Brown , Srinivas Pandruvada , Chen Yu >> for the past few months, I'm fighting random hard lock-ups on my >> Baytrail machine with different linux kernels. Freezes are quite >> frequent, between few minutes to few hours of uptime. According to other >> reporters, this was pinpointed as an intel_idle problem on Baytrail. The >> bug report originally started as i915 regression at >> https://bugs.freedesktop.org/show_bug.cgi?id=88012 and was moved to >> kernel Bugzilla few months ago - >> https://bugzilla.kernel.org/show_bug.cgi?id=109051 >> >> This bug seems to be a serious showstopper for Baytrail users and was >> already confirmed by many, but there is no obvious progress on this bug >> report for last few months. Meny reporters have confirmed >> intel_idle.max_cstate=1 or intel_idle.max_cstate=2 as a half-working >> workaround, which makes the interval between freezes on Baytrail longer. > No, it hasn't, but it turns out difficult to root-cause. > > Tell me one thing: does disabling intel_idle entirely on the affected systems > make the problem go away? > > That is, does intel_idle.max_cstate=0 in the kernel command line help? > > Or does idle=nomwait in the kernel command line help? intel_idle.max_cstate=1 - no hard-lockups intel_idle.max_cstate=0 - no hard-lockups idle=nomwait - with hard-lockups Someone on Bugzilla suggested to try latest 4.5 kernel, as he believes it's fixed already on his BYT laptop. I'm running on the longterm branch so I just upgraded to 4.1.19 LTS which is the latest in Arch distro for the moment. And yes - my uptime is 4 hours and still counting! :-) I'll see during next few days but maybe it's fixed. intel_idle would then be probably out of suspision, as it haven't been touched for last few months.. Michael