Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754651AbYHSMtg (ORCPT ); Tue, 19 Aug 2008 08:49:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753343AbYHSMtZ (ORCPT ); Tue, 19 Aug 2008 08:49:25 -0400 Received: from web82105.mail.mud.yahoo.com ([209.191.84.218]:20174 "HELO web82105.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753312AbYHSMtY (ORCPT ); Tue, 19 Aug 2008 08:49:24 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=sbcglobal.net; h=Received:X-Mailer:Date:From:Subject:To:Cc:MIME-Version:Content-Type:Message-ID; b=dURU99T2o/qenhxnSlnd9eKt1RCD6M8EzbUzhAg0a+Bw5nWY5QA/5Tps166NE2WbxsLBZ/6sEJXjBSBGYv9Blz97bmRVVi/6hC5VOX6oIGDTh282LE6mjTyKwyI5Jtx5DN2Qyg4b+Z+cQ+9vB7/uCEAGkhjhJVUsNmk10sMjn/s=; X-Mailer: YahooMailRC/1042.40 YahooMailWebService/0.7.218 Date: Tue, 19 Aug 2008 05:49:23 -0700 (PDT) From: David Witbrodt Subject: Re: HPET regression in 2.6.26 versus 2.6.25 -- connection between HPET and lockups found To: Ingo Molnar Cc: Yinghai Lu , linux-kernel@vger.kernel.org, "Paul E. McKenney" , Peter Zijlstra , Thomas Gleixner , "H. Peter Anvin" , netdev MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Message-ID: <452065.84245.qm@web82105.mail.mud.yahoo.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2511 Lines: 76 > Just to make sure: on a working kernel, do you get the HPET messages? > I.e. does the hpet truly work in that case? On the "fileserver", where 2.6.25 works but 2.6.26 locks up, the HPET _does_ work on a working kernel: $ uname -r 2.6.26.revert1 $ dmesg | grep -i hpet ACPI: HPET 77FE80C0, 0038 (r1 RS690 AWRDACPI 42302E31 AWRD 98) ACPI: HPET id: 0x10b9a201 base: 0xfed00000 hpet clockevent registered hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0, 0 hpet0: 4 32-bit timers, 14318180 Hz hpet_resources: 0xfed00000 is busy What I didn't realize is that the "desktop" machine, where 2.6.26 has always "worked", does NOT have a working HPET after all, even though I have enabled all HPET options in .config: $ uname -r 2.6.26.080801.desktop.uvesafb $ dmesg | grep -i hpet $ This means I misunderstood my situation on "desktop". I believed HPET was working on all of my machines, but now I am not certain that it ever worked on "desktop" since I built it (May 2007). The question never arose before, and because I enabled the HPET option in .config, I just assumed that HPET was working. (Duh...) I failed to look into this until now. At any rate, my subject line is still accurate: there _is_ an HPET regression on "fileserver" (and "webserver"), since it worked on 2.6.25 kernels but causes lockups on 2.6.2[67] kernels. (I don't know what is going on with "desktop": does the motherboard lack HPET, or does the Linux kernel not support the HPET hardware on the motherboard?) BTW: the 'dmesg' output above is the same on "desktop" with 2.6.25 and 2.6.26 -- I just checked to be sure. For "fileserver", I checked an old 2.6.25 kernel just now, and the output is identical. Another experiment: I just tried this... static __init int hpet_insert_resource(void) { - if (!hpet_res) + /* if (!hpet_res) */ return 1; - return insert_resource(&iomem_resource, hpet_res); + /* return insert_resource(&iomem_resource, hpet_res); */ } ... and the lock up still occurs. So, the memory is allocated but the resource info is not inserted into the tree. Whether the dynamic memory for hpet_res is being damaged or not has no bearing on the lockups, it would seem. Looks like I was barking up the wrong tree.... Dave W. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/