From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Piel Subject: Re: Kernel panic at boot with ondemand governor as default (2.6.24-rc2) Date: Tue, 13 Nov 2007 00:09:46 +0100 Message-ID: <4738DD3A.1080109@lifl.fr> References: <4737539F.2070401@lifl.fr> <1194859012.4590.595.camel@queen.suse.de> <47385D05.20705@lifl.fr> <1194880989.5474.12.camel@queen.suse.de> <20071112202629.GA31763@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20071112202629.GA31763@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: Content-Type: text/plain; charset="utf-8"; format="flowed" To: Dave Jones , Thomas Renninger , linux-kernel@vger.kernel.org, Venkatesh Pallipadi , cpufreq 2007=E5=B9=B411=E6=9C=8812=E6=97=A5 21:26, Dave Jones wrote/a =C3=A9cri= t: > On Mon, Nov 12, 2007 at 04:23:09PM +0100, Thomas Renninger wrote: > > On Mon, 2007-11-12 at 15:02 +0100, Eric Piel wrote: : > > > Yes, it works if I compile speedstep-ich as module. I've put the= module=20 > > > in initramfs and as soon it is loaded, the ondemand governor is = selected=20 > > > and works. > > >=20 > > > However, do you think it's ok to prevent cpufreq drivers to be b= uilt-in=20 > > > if ondemand governor is selected as default? > > > Another way would be to=20 > > > reorganise the initialisation code so that workqueue is initiali= sed=20 > > > before the cpufreq framework is started, do you think it's possi= ble? > > Making all this work with low-level drivers built in would be perf= ect of > > course... > > If nobody answers the next days, could you open a bug at > > bugzilla.kernel.org, so that this does not get lost, pls. > > Add myself and Venkatesh to CC... > > I try to have a look at it ASAP. > > If someone already finds out more, this would be great. >=20 > I'm actually surprised that speedstep-ich works with a low enough > latency for ondemand. On the kernel that works, can you boot > with cpufreq.debug=3D7 and send the cpufreq messages from dmesg? I'm not surprised, contrarly to speedstep-smi, speedstep-ich has been=20 working with ondemand for quite a long time, since commit=20 1a10760c91c394dfe4adfefeeaf85cd8098c4894 precisely :-) As stated in the= =20 commit message, the latency transition is about 200=C2=B5s, much smalle= r than=20 the 10ms required by ondemand. Actually, on my laptop the transition=20 time is set to even higher due to problems of measurement, but it's=20 still fine for ondemand. I get this at boot: speedstep: frequency transition measured seems out of range (4800 nSec)= ,=20 falling back to a safe one of 500000 nSec. See you, Eric