On Sun, 10 Aug 2008 18:29:20 +0200 Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxx For development, discussion and tips for power savings, visit http://www.lesswatts.org -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
