From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Magenheimer Subject: RE: dom0 is stalled until a keypress Date: Tue, 6 Sep 2011 08:49:07 -0700 (PDT) Message-ID: <36a5b662-4420-41aa-be01-445f83b15a7b@default> References: <20110905091937.GA1906@email> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20110905091937.GA1906@email> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Rafal Wojtczuk , xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org > From: Rafal Wojtczuk [mailto:rafal@invisiblethingslab.com] > Sent: Monday, September 05, 2011 3:20 AM > To: xen-devel@lists.xensource.com > Subject: [Xen-devel] dom0 is stalled until a keypress >=20 > Hello, > The following bizarre behaviour was observed on xen4.1+suse dom0 2.6.38, = on > an old Core Duo laptop; maybe someone can hint what is wrong. > Dom0 boot stalls after an init.d script prints "Starting udev". Then noth= ing > seems to happen. I need to press any key to observe progress - I need to = do > it tens of times for the boot to finish. After X starts fine, then there = is > no need for keypressing anymore. > A particularly disturbing fact is that qrexec_daemon parent, that basical= ly > does > for (;;) { sleep(1); fprintf(stderr, "."); } > does not print dots, until a keypress arrives. So something is very wrong > with timers. > Somehow similarly, pm-suspend sometimes hangs at some stage - after detac= hing > power cord, machine enters S3 immediately. > This is vaguely similar to the issue described in > https://lkml.org/lkml/2008/9/14/122 > but this time, "nohz=3Doff" does not help. >=20 > "cpufreq=3Ddom0-kernel" cures the symptoms; but it is not a sideeffectles= s > solution. Any idea what is going on or how to debug it ? ISTR seeing this on a Core(2?)Duo laptop and I think the workaround was setting max_cstate=3D0 (as Xen boot parameter).