Re: CVS commit: src/sys/dev/pci

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sat, Jan 31, 2009 at 06:40:24PM -0600, David Young wrote:
> > Log Message:
> > Under some circunstance, the JMC250A2 (and maybe others) can enter a state
> > where INTA is asserted while no enabled interrupts are pending, which
> > cause a continous strean if interrupts with no way to clear it.
> > Clearing/resetting the enabled interrupt mask in the interrupt handler seems
> > to workaround this issue (this is what the FreeBSD driver does).
> > While there properly return 0 if the interrupt was not for us, and 
> > explicitely
> > disable JME_TMCSR in addition to TIMER1 and TIMER2.
> 
> Does FreeBSD enable/disable by changing the interrupt mask on the
> NIC because that is the right / only workaround for this bug, or
> do they do that because the change has been carried by the cargo
> cult from driver to driver to driver?

They do it because it's the right thing to do in their interrupt system
(the interrupt handler defers interrupt processing to a kernel thread).

> Maybe you should disable/enable
> only if INTA seems to be stuck?

How do we know if INTA is stuck ? Especially when it's shared with other
devices ? I guess this will require more cycles than the 2 single
writes to the adapter's registers required to do this.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--