Re: Possible critical VIA vt82c686a chip bug (private question)

From: Yoann Vandoorselaere (yoann@mandrakesoft.com)
Date: Thu Oct 26 2000 - 16:05:04 EST


Vojtech Pavlik <vojtech@suse.cz> writes:

> On Thu, Oct 26, 2000 at 10:11:54PM +0200, Yoann Vandoorselaere wrote:
>
> > > > > > ../drivers/block/ide.c, line 162, on version 2.2.17 does bad things
> > > > > > to the timer. It writes 0 to the control-word for timer 0. This
> > > > > > does the following:
> > > > [Snipped...]
> > > > >
> > > > > Well, at least on 2.4.0-test9, the above timing code is #ifed to
> > > > > DISK_RECOVERY_TIME > 0, which in turn is #defined to 0 in
> > > > > include/linux/ide.h.
> > > > >
> > > > > So this is not our problem here. Anyway I guess it's time to hunt for
> > > > > i8259 accesses in the kernel that lack the necessary spinlock, even when
> > > > > they're not probably the cause of the problem we see here.
> > > >
> > > > Okay, good.
> > >
> > > Ok, here is a list of places within the kernel that access the PIT
> > > timer, plus the method of locking (i386 arch only):
> >
> > [...]
> >
> > Ok, I just tested if the problem was always present without
> > the IDE subsystem...
> >
> > The answer is it is not... so it isn't an IDE problem.
>
> Uh, guess too many negations. You wanted to say that the problem was
> present even when you disabled the IDE subsystem, right?

yop

>
> So now it seems that possibly enough PCI traffic / busmastering traffic
> can cause the problem ...

yop, I 've done :

make -j10 World
in the xfree tree and simulateously :

while true; do make dep && make clean && make bzImage; done
in the kernel tree

-- 
		-- Yoann http://www.mandrakesoft.com/~yoann/
   An engineer from NVidia, while asking him to release cards specs said :
	"Actually, we do write our drivers without documentation."
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