Jeff Garzik writes:
> Mikael Pettersson wrote:
> > Jeff,
> >
> > In the 2.6.8 kernel you added sata_promise.c:pdc_irq_clear()
> > which looks as follows:
> >
> >> static void pdc_irq_clear(struct ata_port *ap)
> >> {
> >> struct ata_host *host = ap->host;
> >> void __iomem *mmio = host->iomap[PDC_MMIO_BAR];
> >>
> >> readl(mmio + PDC_INT_SEQMASK);
> >> }
> >
> > I have two issues with this code:
> > 1. It reads from the SEQMASK register, which is global for
> > all ports. Hence, calling pdc_irq_clear() on one port
> > potentially affects all ports.
> > 2. Promise's drivers (both 1st and 2nd generation chip drivers)
> > instead read the port's ATA Command/Status register when
> > they want to clear any pending IRQs.
> >
> > Did you write the code this way on purpose, or did you just
> > accidentally use the wrong mechanism?
> >
> > If you have no objections, I intend to change this to read
> > Command/Status instead.
>
> For sata_promise, at the time it was written, irq_clear was largely a
> sledgehammer for SFF situations that didn't automatically resolve
> themselves through normal operation. Given the amount of SFF code that
> is _not_ enabled when using sata_promise is in use, ->irq_clear() is
> largely a relic for PIO data xfer situations.
>
> Feel free to replace if you think is appropriate...
Thanks, will do after I've tested it.
/Mikael
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