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sata_nv: don't rely on NV_INT_DEV indication with ADMA

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Several people reported issues with certain drive commands timing out on
sata_nv controllers running in ADMA mode. The commands in question were
non-DMA-mapped commands, usually FLUSH CACHE or FLUSH CACHE EXT.

 From experimentation it appears that the NV_INT_DEV indication isn't
always set when a legitimate command completion interrupt is received on
a legacy-mode command, at least not on these controllers in ADMA mode.
When a command is pending on the port, force the flag on always in the
irq_stat value before calling nv_host_intr so that the drive busy state
is always checked by ata_host_intr.

This also fixes some questionable code in nv_host_intr which called
ata_check_status when a command was pending and ata_host_intr returned
"unhandled". If the device interrupted at just the wrong time this could
cause interrupts to be lost.

Signed-off-by: Robert Hancock <hancockr@shaw.ca>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
This commit is contained in:
Robert Hancock 2007-01-23 20:09:02 -06:00 committed by Jeff Garzik
parent 82490c0937
commit f740d1689d
1 changed files with 6 additions and 8 deletions
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14
drivers/ata/sata_nv.c
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@ -700,7 +700,6 @@ static void nv_adma_check_cpb(struct ata_port *ap, int cpb_num, int force_err)
static int nv_host_intr(struct ata_port *ap, u8 irq_stat)
{
struct ata_queued_cmd *qc = ata_qc_from_tag(ap, ap->active_tag);
int handled;
/* freeze if hotplugged */
if (unlikely(irq_stat & (NV_INT_ADDED | NV_INT_REMOVED))) {
@ -719,13 +718,7 @@ static int nv_host_intr(struct ata_port *ap, u8 irq_stat)
}
/* handle interrupt */
handled = ata_host_intr(ap, qc);
if (unlikely(!handled)) {
/* spurious, clear it */
ata_check_status(ap);
}
return 1;
return ata_host_intr(ap, qc);
}
static irqreturn_t nv_adma_interrupt(int irq, void *dev_instance)
@ -752,6 +745,11 @@ static irqreturn_t nv_adma_interrupt(int irq, void *dev_instance)
if (pp->flags & NV_ADMA_PORT_REGISTER_MODE) {
u8 irq_stat = readb(host->mmio_base + NV_INT_STATUS_CK804)
>> (NV_INT_PORT_SHIFT * i);
if(ata_tag_valid(ap->active_tag))
/** NV_INT_DEV indication seems unreliable at times
at least in ADMA mode. Force it on always when a
command is active, to prevent losing interrupts. */
irq_stat |= NV_INT_DEV;
handled += nv_host_intr(ap, irq_stat);
continue;
}