[patch 055/101] sata_sil: ignore and clear spurious IRQs while executing commands by polling

[Greg KH]

sata_sil used to trigger HSM error if IRQ occurs during polling
command.  This didn't matter because polling wasn't used in sata_sil.
However, as of 2.6.20, all IDENTIFYs are performed by polling and
device detection sometimes fails due to spurious IRQ.  This patch
makes sata_sil ignore and clear spurious IRQ while executing commands
by polling.

This fixes bug#7996 and IMHO should also be included in -stable.

Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
Cc: Jeff Garzik <jeff@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/ata/sata_sil.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- linux-2.6.20.1.orig/drivers/ata/sata_sil.c
+++ linux-2.6.20.1/drivers/ata/sata_sil.c
@@ -383,9 +383,15 @@ static void sil_host_intr(struct ata_por
 		goto freeze;
 	}
 
-	if (unlikely(!qc || qc->tf.ctl & ATA_NIEN))
+	if (unlikely(!qc))
 		goto freeze;
 
+	if (unlikely(qc->tf.flags & ATA_TFLAG_POLLING)) {
+		/* this sometimes happens, just clear IRQ */
+		ata_chk_status(ap);
+		return;
+	}
+
 	/* Check whether we are expecting interrupt in this state */
 	switch (ap->hsm_task_state) {
 	case HSM_ST_FIRST:

--
-
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