sata_sil: ignore and clear spurious IRQs while executing commands by polling

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.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/ata/sata_sil.c b/drivers/ata/sata_sil.c
index 14872556334b..aaff357db5f5 100644
--- a/drivers/ata/sata_sil.c
+++ b/drivers/ata/sata_sil.c
@@ -386,9 +386,15 @@ static void sil_host_intr(struct ata_port *ap, u32 bmdma2)
                 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: