Re: [Bisected] Regression: Hang on boot inschedule_timeout_interruptible during ACPI init on SMP

[Glauber Costa]

On Sat, Jul 26, 2008 at 02:53:11PM -0400, Andrew Drake wrote:
> I just discovered; the nolapic_timer parameter causes the problem to go 
> away entirely. It doesn't seem to have any nasty side effects, so I'm 
> content to use it. Looking at the dmesg logs, however, I notice that the 
> "last-good" kernel doesn't even try to use the LAPIC timer, but the 
> "first-bad" does. I wasn't able to track down any discernible reason.
fine, but if you can still help us on this, it would be awesome ;-)

Actually, there is another nasty bug that depends, at least by a first
impression, on the lapic timer. I'm planning to save a time today to
look further on your problem.
>
> On a side note, that's the first I've ever heard/seen of that parameter, 
> I tried it because I noticed the problems started when the LAPIC timer 
> was successfully set up. I doubt the average user would notice this (you 
> can't even tell unless you pass apic=debug), so I doubt many others would 
> discover this fix/workaround.
>
> The question remains, though, why did it go from "don't try" to "try"?

Probably because the order of initialization of smp entities changed a
bit during this series. Probably the lapic timer is now initialized a
little bit earlier, before we have the chance to mark it as bad.

If you can send me at least your dmesgs and cpuinfo, it would be really really
awesome.

> Thanks,
>
> Andrew
>
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