The DMA_IRQ bit in the bmdma status register is always set when IDEIRQ
is asserted allowing spurious IRQ detection. Detect spurious IRQs and
clear them. This protects ata_piix against nobody-cared which gets
reported not so rarely.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
drivers/ata/ata_piix.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 53 insertions(+), 1 deletion(-)
diff --git a/drivers/ata/ata_piix.c b/drivers/ata/ata_piix.c
index 8e37be1..b438edc 100644
--- a/drivers/ata/ata_piix.c
+++ b/drivers/ata/ata_piix.c
@@ -922,6 +922,58 @@ static int piix_sidpr_scr_read(struct ata_link *link,
return 0;
}
+static irqreturn_t piix_interrupt(int irq, void *dev_instance)
+{
+ struct ata_host *host = dev_instance;
+ unsigned int i;
+ unsigned int handled = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&host->lock, flags);
+
+ for (i = 0; i < host->n_ports; i++) {
+ struct ata_port *ap = host->ports[i];
+ struct ata_queued_cmd *qc;
+ u8 host_stat;
+
+ if (ata_port_is_dummy(ap))
+ continue;
+
+ qc = ata_qc_from_tag(ap, ap->link.active_tag);
+ if (qc && !(qc->tf.flags & ATA_TFLAG_POLLING)) {
+ handled |= ata_sff_host_intr(ap, qc);
+ continue;
+ }
+
+ /*
+ * Control reaches here if HSM is not expecting IRQ.
+ * If the controller is actually asserting IRQ line,
+ * this will lead to nobody cared. Fortuantely,
+ * DMA_INTR of PIIX is set whenever IDEIRQ is set so
+ * it can be used to detect spurious IRQs. As the
+ * driver is not expecting IRQ at all, clearing IRQ
+ * here won't lead to loss of IRQ event.
+ */
+ if (unlikely(!ap->ioaddr.bmdma_addr))
+ continue;
+
+ host_stat = ap->ops->bmdma_status(ap);
+ if (!(host_stat & ATA_DMA_INTR))
+ continue;
+
+ if (printk_ratelimit())
+ ata_port_printk(ap, KERN_INFO,
+ "clearing spurious IRQ\n");
+ ap->ops->sff_check_status(ap);
+ ap->ops->sff_irq_clear(ap);
+ handled |= 1;
+ }
+
+ spin_unlock_irqrestore(&host->lock, flags);
+
+ return IRQ_RETVAL(handled);
+}
+
static int piix_sidpr_scr_write(struct ata_link *link,
unsigned int reg, u32 val)
{
@@ -1470,7 +1522,7 @@ static int __devinit piix_init_one(struct pci_dev *pdev,
}
pci_set_master(pdev);
- return ata_pci_sff_activate_host(host, ata_sff_interrupt, &piix_sht);
+ return ata_pci_sff_activate_host(host, piix_interrupt, &piix_sht);
}
static int __init piix_init(void)
--
To unsubscribe from this list: send the line "unsubscribe linux-ide" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
