Re: [smartmontools-support] inactive SATA drives won't stay in standbyor sleep, PATA models did. (fwd)

[Mikael Pettersson]

Tejun Heo writes:
 > Hello, Mikael.
 > 
 > > --- linux-2.6.27/drivers/ata/sata_promise.c.~1~	2008-07-14 10:22:36.000000000 +0200
 > > +++ linux-2.6.27/drivers/ata/sata_promise.c	2008-10-20 00:20:58.000000000 +0200
 > > @@ -153,6 +153,7 @@ static void pdc_freeze(struct ata_port *
 > >  static void pdc_sata_freeze(struct ata_port *ap);
 > >  static void pdc_thaw(struct ata_port *ap);
 > >  static void pdc_sata_thaw(struct ata_port *ap);
 > > +static int pdc_prereset(struct ata_link *link, unsigned long deadline);
 > >  static void pdc_error_handler(struct ata_port *ap);
 > >  static void pdc_post_internal_cmd(struct ata_queued_cmd *qc);
 > >  static int pdc_pata_cable_detect(struct ata_port *ap);
 > > @@ -175,6 +176,7 @@ static const struct ata_port_operations 
 > >  	.sff_irq_clear		= pdc_irq_clear,
 > >  
 > >  	.post_internal_cmd	= pdc_post_internal_cmd,
 > > +	.prereset		= pdc_prereset,
 > >  	.error_handler		= pdc_error_handler,
 > >  };
 > >  
 > > @@ -691,6 +693,12 @@ static void pdc_sata_thaw(struct ata_por
 > >  	readl(host_mmio + hotplug_offset); /* flush */
 > >  }
 > >  
 > > +static int pdc_prereset(struct ata_link *link, unsigned long deadline)
 > > +{
 > > +	pdc_reset_port(link->ap);
 > 
 > I would put this into ->hardreset itself as the controller can also
 > get out of sync with reality during reset.

The only thing I see going on between prereset and (hard/soft)reset
is an optional freeze, so I don't see why moving the pdc_reset_port()
into the beginning of hardreset() would make any difference.

sata_promise currently uses the ->hardreset and ->softreset inherited
from ata_sff_port_ops, so it would need to override both to ensure that
we always do pdc_reset_port() before libata does its thing. That's why
I felt doing that in ->prereset would be the right solution.

/Mikael
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