Messages in this thread | | | Date | Fri, 9 May 2008 16:30:43 -0300 | From | "Carlos R. Mafra" <> | Subject | Re: RFC: starting a kernel-testers group for newbies |
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On Fri 9.May'08 at 12:32:51 -0400, Mark Lord wrote: > Pallipadi, Venkatesh wrote: >> >>> -----Original Message----- >>> From: linux-kernel-owner@vger.kernel.org >>> [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of Carlos R. Mafra >>> Sent: Friday, May 02, 2008 10:16 AM >>> To: Linus Torvalds >>> Cc: Adrian Bunk; Paul Mackerras; Josh Boyer; Arjan van de Ven; Andrew >>> Morton; Rafael J. Wysocki; davem@davemloft.net; >>> linux-kernel@vger.kernel.org; jirislaby@gmail.com; Steven Rostedt; >>> Pallipadi, Venkatesh >>> Subject: Re: RFC: starting a kernel-testers group for newbies >>> >>> On Fri 2.May'08 at 9:28:08 -0700, Linus Torvalds wrote: >>> >>>> Quite frankly, it does sound like the hang happens somewhere >>> around the >>>> hpet_init >>>> hpet_acpi_add >>>> hpet_resources >>>> hpet_resources: 0xfed00000 is busy >>>> >>>> printk's you added (correct?) and we've had tons of issues >>> with NO_HZ, so >>>> at a guess it is timer-related. >>> It happens a bit before that because when it hangs it doesn't print the >>> above lines, and when it does not hang these lines are >>> the ones right after the point where it hangs. >>>> (And I assume it's stable if/once it gets past that boot hang issue? >>> Yes you are right. When I have luck and the boot succeeds my Sony laptop >>> is rock solid and the kernel is wonderful (even the card reader works!). >>> >>>> That >>>> tends to mean that it's not some hardware instability, it's >>> literally our >>>> init code). >>> A few days ago I found this message in lkml in reply to a hpet patch >>> http://lkml.org/lkml/2007/5/7/361 in which the reporter also had a >>> similar hang, which was cured by hpet=disable. >>> So it is in my TODO list to try to check out if that patch is in the >>> current -git and whether it can be reverted somehow (I added Venki to the >>> Cc: now) >>> >>> Thanks a lot for the answer! >> >> It depends on whether we are HPET is being force detected based on the >> chipset or whether it was exported by the BIOS in ACPI table. >> >> If it was force enabled and above patch is having any effect, then you >> should see a message like >>> Force enabled HPET at base address 0xfed00000 >> >> In any case, off late there seems to be quite a few breakages that are >> related to HPET/timer interrupts. One of them was on a system which has >> HPET being exported by BIOS >> http://bugzilla.kernel.org/show_bug.cgi?id=10409 >> And the other one where we are force enabling based on chipset >> http://bugzilla.kernel.org/show_bug.cgi?id=10561 >> >> And then we have hangs once in a while reports by you, Roman and Mark >> here >> http://bugzilla.kernel.org/show_bug.cgi?id=10377 >> http://bugzilla.kernel.org/show_bug.cgi?id=10117 > .. > > Yeah. This particular bug first appeared when NOHZ & HPET were added. > Somebody once suggested it had something to do with an SMI interrupt > happening in the midst of HPET calibration or some such thing. >
I said I was waiting for -rc1 to be released to send another email about my HPET problem, but curiously with v2.6.26-rc1-6-gafa26be my laptop did not hang after 30+ boots and counting.
Somewhere between 2.6.25-07000-(something) and the above kernel something happened which changed significantly the probability of hanging during boot.
I could not boot more than 3 times in a row without hanging with kernels up to 2.6.25-07000 (approximately), and now I am still booting v2.6.26-rc1-6-gafa26be a few times a day and no hangs yet.
Yesterday I started a "reverse" bisection, trying to find which commit "fixed" it, but I still didn't finish (but it is past -7200).
Of course I am not sure if after the 100th boot the latest -git won't hang but it definitely improved.
> But nobody who works on the HPET code has ever shown more than a casual > interest in helping to track down and fix whatever the problem is.
Well, I would like to thank Venki for his effort because he even answered some private emails from me about this issue and is tracking the bugzillas about it.
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