Re: [PATCH] pata_isapnp: Don't use invalid I/O ports

[Ondrej Zary <linux@rainbow-software.org>]

On Sunday 22 September 2013 18:49:42 Tejun Heo wrote:
> Hello, Ondrej.
>
> On Fri, Sep 13, 2013 at 11:44:27PM +0200, Ondrej Zary wrote:
> > This is caused by skipping ata_sff_softreset() when ap->ioaddr.ctl_addr
> > is unset so ata_devchk() is never called. This patch seems to fix the
> > problem. Is it OK or can it cause more problems?
> >
> > --- a/drivers/ata/libata-sff.c
> > +++ b/drivers/ata/libata-sff.c
> > @@ -2008,13 +2008,15 @@ static int ata_bus_softreset(struct ata_port *ap,
> > unsigned int devmask,
> >
> >  	DPRINTK("ata%u: bus reset via SRST\n", ap->print_id);
> >
> > -	/* software reset.  causes dev0 to be selected */
> > -	iowrite8(ap->ctl, ioaddr->ctl_addr);
> > -	udelay(20);	/* FIXME: flush */
> > -	iowrite8(ap->ctl | ATA_SRST, ioaddr->ctl_addr);
> > -	udelay(20);	/* FIXME: flush */
> > -	iowrite8(ap->ctl, ioaddr->ctl_addr);
> > -	ap->last_ctl = ap->ctl;
> > +	if (ap->ioaddr.ctl_addr) {
> > +		/* software reset.  causes dev0 to be selected */
> > +		iowrite8(ap->ctl, ioaddr->ctl_addr);
> > +		udelay(20);	/* FIXME: flush */
> > +		iowrite8(ap->ctl | ATA_SRST, ioaddr->ctl_addr);
> > +		udelay(20);	/* FIXME: flush */
> > +		iowrite8(ap->ctl, ioaddr->ctl_addr);
> > +		ap->last_ctl = ap->ctl;
> > +	}
> >
> >  	/* wait the port to become ready */
> >  	return ata_sff_wait_after_reset(&ap->link, devmask, deadline);
> > @@ -2215,10 +2217,6 @@ void ata_sff_error_handler(struct ata_port *ap)
> >
> >  	spin_unlock_irqrestore(ap->lock, flags);
> >
> > -	/* ignore ata_sff_softreset if ctl isn't accessible */
> > -	if (softreset == ata_sff_softreset && !ap->ioaddr.ctl_addr)
> > -		softreset = NULL;
> > -
> >  	/* ignore built-in hardresets if SCR access is not available */
> >  	if ((hardreset == sata_std_hardreset ||
> >  	     hardreset == sata_sff_hardreset) && !sata_scr_valid(&ap->link))
>
> Hmm... I'm unsure what to do with these patches.  It's a mostly dead
> driver, so I don't wanna mess with it too much unless it's an obvious
> fix.  What hardware are you playing with?

IMHO, the first patch (invalid I/O ports) is an obvious fix. That bug causes 
problems with ES968 sound cards.

The second patch is not-so-obvious. Only few ATA controllers don't have 
control register, but they're all broken now. I'm not sure if the patch is 
100% correct but it seems to work fine and it does not affect most 
controllers.

-- 
Ondrej Zary