On Sat, 2007-05-05 at 01:18 +0200, Andi Kleen wrote: > On Friday 04 May 2007 23:29:04 john stultz wrote: > > One of the 2.6.21 regressions was Guilherme's problem seeing his box > > lock up when the system detected an unstable TSC and dropped back to > > using the HPET. > > > > In digging deeper, we found the HPET is not actually incrementing on > > this system. And in fact, the reason why this issue just cropped up was > > because of Thomas's clocksource watchdog code was comparing the TSC to > > the HPET (which wasn't moving) and thought the TSC was broken. > > > > Anyway, Guliherme checked for a BIOS update and did not find one, so > > I've added a DMI blacklist against his system so the HPET is not used. > > > > Many thanks to Guilherme for the slow and laborious testing that finally > > narrowed down this issue. > > Before going to hard to maintain DMI black lists we should first check > if it's a more general problem and can't it be solved better? Most likely > that system isn't the one with this issue and I don't want to apply > DMI patches forever.
We can give it a whirl, I just didn't want to add yet another "compare with some other counter that may or may not work" check. In this case, probably reading three times in a row and getting the same result would be a clearly broken box. > In particular: what lspci chipset does it have? If it's Intel it might be > worth checking the datasheet if there is some "HPET stop" bit -- perhaps it > could be fixed up. Guilherme: Could you provide lspci output? > We seem to have a couple of Intel systems recently with HPET trouble. Ok, I wasn't aware it was a common issue. thanks -john - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/