Hi Tejun,
> -----Original Message-----
> From: Huang, Shane
>
> > > +static void ahci_fbs_dec_intr(struct ata_port *ap)
> > > +{
> > > + struct ahci_port_priv *pp = ap->private_data;
> > > + DPRINTK("ENTER\n");
> > > +
> > > + if (pp->fbs_enabled) {
> >
> > Just do BUG_ON(!pp->fbs_enabled);
>
> OK.
>
>
> > > + void __iomem *port_mmio = ahci_port_base(ap);
> > > + u32 fbs = readl(port_mmio + PORT_FBS);
> > > + int retries = 3;
> > > +
> > > + /* time to wait for DEC is not specified by AHCI spec,
> > > + * add a retry loop for safety */
> > > + do {
> > > + writel(fbs | PORT_FBS_DEC, port_mmio +
> > PORT_FBS);
> > > + fbs = readl(port_mmio + PORT_FBS);
> > > + retries--;
> > > + } while ((fbs & PORT_FBS_DEC) && retries);
At the 2nd thought, if (!pp->fbs_enabled) appears unfortunately
(although it should not), replacement of if (pp->fbs_enabled) with
BUG_ON() will lead to the execution of the followed DEC, which
might lead to indeterminate result, because of AHCI v1.2 3.3.16:
Device Error Clear (DEC): ....... Software shall only set this bit to
'1' if
PxFBS.EN is set to '1' and PxFBS.SDE is set to '1'.
So I would suggest to keep my original implementation in v2, or put
BUG_ON to the else case, if you insist, to replace the original
dev_printk(KERN_ERR).
Thanks
Shane
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