From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arjan van de Ven Subject: Re: ACPI PM-Timer on K6-3 SiS5591: Houston... Date: Sun, 10 Aug 2008 09:40:38 -0700 Message-ID: <20080810094038.141480b4@infradead.org> References: <20080810101730.GA10024@rhlx01.hs-esslingen.de> <20080810162920.GA9860@comet.dominikbrodowski.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from casper.infradead.org ([85.118.1.10]:49107 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751472AbYHJQkd (ORCPT ); Sun, 10 Aug 2008 12:40:33 -0400 In-Reply-To: <20080810162920.GA9860@comet.dominikbrodowski.net> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Dominik Brodowski Cc: Andreas Mohr , LKML , john stultz , OGAWA Hirofumi , Alan Cox , linux-acpi@vger.kernel.org On Sun, 10 Aug 2008 18:29:20 +0200 Dominik Brodowski wrote: > Hi Andreas, > > On Sun, Aug 10, 2008 at 12:17:30PM +0200, Andreas Mohr wrote: > > Result: catastrophic timer behaviour (a large backwards skip is > > possible), even in case we do a triple-read workaround, due to a > > floating bit at 0x0400 (possibly caused by underclocking from 400 > > to 150, but whatever...). > > this isn't the bug which is handled by the > read-three-times-workaround. Instead, that handels the following > PIIX4 errata: > > * PIIX4 Errata: > * > * The power management timer may return improper results when read. > * Although the timer value settles properly after incrementing, > * while incrementing there is a 3 ns window every 69.8 ns where the > * timer value is indeterminate (a 4.2% chance that the data will be > * incorrect when read). As a result, the ACPI free running count up > * timer specification is violated due to erroneous reads. > > > And my system does pass the bootup PM-Timer check quite often > > despite this severe defect (2 in 4 bootups _did_ register my > > defective acpi_pm clocksource). > > No surprise there -- it is the first time I see such an error; and it > might actually be a bug specific to your computer's motherboard. > if it's really only one board that's faulty... a dmi blacklist might be appropriate. -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org