From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030219AbWGFGjF (ORCPT ); Thu, 6 Jul 2006 02:39:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030224AbWGFGjF (ORCPT ); Thu, 6 Jul 2006 02:39:05 -0400 Received: from pool-72-66-201-79.ronkva.east.verizon.net ([72.66.201.79]:45507 "EHLO turing-police.cc.vt.edu") by vger.kernel.org with ESMTP id S1030219AbWGFGjE (ORCPT ); Thu, 6 Jul 2006 02:39:04 -0400 Message-Id: <200607060638.k666cf8V003016@turing-police.cc.vt.edu> X-Mailer: exmh version 2.7.2 01/07/2005 with nmh-1.2 To: Roman Zippel Cc: john stultz , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: 2.6.17-mm2 hrtimer code wedges at boot? In-Reply-To: Your message of "Thu, 06 Jul 2006 02:37:25 +0200." From: Valdis.Kletnieks@vt.edu References: <20060624061914.202fbfb5.akpm@osdl.org> <200606262141.k5QLf7wi004164@turing-police.cc.vt.edu> <200606271643.k5RGh9ZQ004498@turing-police.cc.vt.edu> <200606271907.k5RJ7kdg003953@turing-police.cc.vt.edu> <1151453231.24656.49.camel@cog.beaverton.ibm.com> <200606292307.k5TN7MGD011615@turing-police.cc.vt.edu> <1151695569.5375.22.camel@localhost.localdomain> <200606302104.k5UL41vs004400@turing-police.cc.vt.edu> <200607050429.k654TXUr012316@turing-police.cc.vt.edu> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1152167921_2733P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Thu, 06 Jul 2006 02:38:41 -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --==_Exmh_1152167921_2733P Content-Type: text/plain; charset=us-ascii On Thu, 06 Jul 2006 02:37:25 +0200, Roman Zippel said: > Ok, I see now the problem, the last cycle value is always at least 50 > times incremented between adjustments and that also means any error > adjustment is applied at least 50 times, which quickly gets out of > control. > Is it possible that your console output is really slow? Otherwise I can't > explain these numbers, everything looks initialized fine for a 1.6GHz > clock, but it seems to take ages to print a single line. Oh.. this is a real Homer Simpson moment.... "D'Oh!" :) The grub definition: title 2.6.17-mm2 testing kernel /vmlinuz-2.6.17-mm2-test single console=tty0 vga=794 initrd /initrd-selinux.img Yes, this laptop has a real actual DB-9 serial port on the back, and I've had it defined as a console for forever (since trying to debug a problem against 2.5.60 or so). So maybe that's where it's coming from. But a quick boot test or 3 shows the console=tty0 isn't the problem. It turns out to be the 'vga=794', which selects this mode: [ 16.633604] Console: colour dummy device 80x25 [ 17.685983] Console: switching to colour frame buffer device 160x64 And we promptly get a timing problem. I tried booting with 'vga=ask' and choosing mode 1, and got this mode instead: [ 31.003715] Console: colour VGA+ 80x50 And things came up fine at that point. Apparently, trying to scroll a big 160x64 is sufficiently slower than scrolling an 80x50 to trigger the problem. I'd look at John's patch in the morning: > Implement P-D control for clocksource_adjust() > diff --git a/kernel/timer.c b/kernel/timer.c > index 396a3c0..f4e7681 100644 > --- a/kernel/timer.c > +++ b/kernel/timer.c > @@ -1007,81 +1007,108 @@ static int __init timekeeping_init_devic Too many 2:30AM's in the past 2 weeks for a guy my age.. (Actually, the 2:30AM isn't the problem - it's the office hours 7 hours later. ;) --==_Exmh_1152167921_2733P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.4 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iD8DBQFErK/xcC3lWbTT17ARAmJkAJwIXej8/Jx09YSak22rMC9Xn0N4RACdHVBB 2gLPCv9RMG01xBf1wAdSPnw= =mIlg -----END PGP SIGNATURE----- --==_Exmh_1152167921_2733P--