On Fri, 2007-05-04 at 20:42 -0400, Jeff Garzik wrote: > 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 PROTECTED]> > > 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.
We had a discussion about 2 years ago and David decided to remove the I/O read to improve performance. Since then a small number of users have been complaining about spurious interrupts. We can add back the unconditional read or do this detection thing which I agree is somewhat annoying. David, what do you think? - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
