Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1767070AbXEBSKS (ORCPT ); Wed, 2 May 2007 14:10:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1767076AbXEBSKR (ORCPT ); Wed, 2 May 2007 14:10:17 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.142]:54684 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1767070AbXEBSKP (ORCPT ); Wed, 2 May 2007 14:10:15 -0400 Subject: Re: Fw: [BUG 2.6.21-rc7] acpi_pm clocksource loses time on x86-64 From: john stultz To: Mikael Pettersson Cc: Len Brown , Thomas Gleixner , lkml , Andi Kleen In-Reply-To: <200704291524.l3TFOL9j013216@harpo.it.uu.se> References: <200704291524.l3TFOL9j013216@harpo.it.uu.se> Content-Type: text/plain Date: Wed, 02 May 2007 11:10:09 -0700 Message-Id: <1178129409.6183.12.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1609 Lines: 47 On Sun, 2007-04-29 at 17:24 +0200, Mikael Pettersson wrote: > On Thu, 26 Apr 2007 15:42:44 -0700, john stultz wrote: > >Another shot in the dark: > > > >I wonder if the ACPI PM counter is halting in idle. Does booting w/ > >idle=poll change the behavior? (Please do this while your laptop is > >plugged in, as it will run the cpu at full speed all the time). > > Bingo! Awesome! Finally, some progress! Thanks again for putting up w/ all my testing requests. > I booted the x86-64 2.6.21 final kernel with idle=poll and let the > laptop idle for an hour. The ondemand cpufreq governor did reduce > the CPU's clock frequency, but that shouldn't have affected the > chipset or the ACPI PM counter. > > Anyway, after 60 minutes `date' and `hwclock' were still in perfect > sync and matched actual time. > > Any ideas why this halting in idle doesn't happen with the 32-bit kernel? No clue. Time to ask Len. :) Hey Len, So that slow acpi_pm on x86_64 seems to be connected w/ the idle loop. I'm guessing the chipset halts the ACPI PM in lower C states. Do you have any guesses as to what might differ between x86_64 and i386 ACPI idle loops? Or might this be something different in what the BIOS exports in x86_64 mode or i386 mode? Any suggestions on how to dig through this? Thomas: Heads up, the ACPI PM might be flakier then we thought. thanks -john - 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/