Subject: Re: [PATCH 10/11][TG3]: Reduce spurious interrupts.

From: Jeff Garzik <[email-masked]>
Date: Fri, 04 May 2007 20:42:43 -0400

Michael Chan wrote:
> [TG3]: Reduce spurious interrupts.
> 
> Spurious interrupts are often encountered especially on systems
> using the 8259 PIC mode.  This is because the I/O write to deassert
> the interrupt is posted and won't get to the chip immediately.  As
> a result, the IRQ may remain asserted after the IRQ handler exits,
> causing spurious interrupts.
> 
> An unconditional read to flush the I/O write to force the IRQ to de-
> assert immediately is not desirable because it impacts performance in
> the fast path.  So we only do this after we have some indications of
> spurious interrupts.
> 
> Signed-off-by: Michael Chan <[email-masked]>

hmmmm, this is a bit questionable that it needs to be here.

I think it's just a fact of life that it is important to flush certain 
writes...

I'm not sure a driver needs to be adding code to avoid the obvious 
solution.  It would be annoying if all drivers had code to do this.

	Jeff