Re: linux-next: Tree for June 13: IO APIC breakage on HP nx6325

From: Rafael J. Wysocki
Date: Sun Jun 29 2008 - 18:57:23 EST


On Sunday, 29 of June 2008, Ingo Molnar wrote:
>
> * Maciej W. Rozycki <macro@xxxxxxxxxxxxxx> wrote:
>
> > You may argue this is a regression, but this is simply the cost paid
> > for progress -- the kernel stays within the spec as defined both by
> > ACPI and MPS, we have just started using a different configuration now
> > and an interrupt source override provided by the manufacturer
> > explicitly states INTIN2 is good to use. In a sense you were simply
> > lucky previously the kernel was bad enough with the way it configured
> > the timer through the I/O APIC it failed completely avoiding the bug
> > in your firmware. Now the bug has got uncovered.
>
> well as long as we eliminate the bad effects around via DMI exceptions
> nobody will feel the need to argue whether it's a regression ;-)

If all boxes affected by this particulare breakage are covered by DMI-based
workarounds, they will continue to work and that won't be any regression.
The point is that the patch should go along with such workarounds.

> [this problem could be argued to be a regression, even if it's caused by
> prior luck/stupidity of Linux. We have to live with the effects of our
> mistakes.]

That's exactly right.

Thanks,
Rafael
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