Re: [BUG FIX] Make x86_32 uni-processor Atomic ops, Atomic

From: Michael S. Zick
Date: Thu May 28 2009 - 16:55:21 EST

On Thu May 28 2009, Pavel Machek wrote:
> Hi!
> > > @hpa - I still like your suggestion that it is only one (or a few)
> > > uses of atomic ops that is incorrect and in general atomic ops
> > > should compile away on uni-processor.
> > >
> >
> > Actually, the more I think about it the more I suspect there is a race
> > condition either in the chip set or in any VIA-specific drivers (if
> > there are any.) Putting LOCKs in random places will slow the CPU down
> > significantly, so it might resolve the race condition without actually
> > solving the problem.
> Which you can verify; replace lock with something slow (pushad,
> popad)? And see what happens.
> (And if it never ever triggers on hp2133, you have strong clue that it
> may not be cpu-related, but bios-related or chipset related or something).
> Some time ago I was trying to debug misterious hangs on some
> via/fic machines.
> We never figured out what was wrong, but we discovered many other bios
> bugs, and those were not being fixed; so debugging was
> hard/impossible. Unfortunately I no longer have access to that hw.

Then I am not losing my mind here - *it is* a difficult problem. ;)

> hp2133 did _not_ have that problem.

Today's build has been playing me music for over 8 hours on the
HP-2133 (C7M-CN896) but can't get past a couple of hours on the
(fic) Everex Cloudbook (C7M-CX700).

Also, the distro on the Cloudbook is using pulse-audio - the
distro on the HP is not. So I am reviewing the recent bug
fixes to kernel/futex for something over-looked. ;)
May be a wild goose chase, but I think pulse-audio uses futexes.

Thanks for the other hints.

> Try forcing maximum throttling, then move mouse for like five
> seconds. If kbc dies, you have same buggy bios, and probably are
> debugging same problem....
> Pavel

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