sata_sil: fix spurious IRQ handling

Interestingly, sata_sil raises spurious interrupts if it's coupled
with Sil SATA_PATA bridge.  Currently, sata_sil interrupt handler is
strict about spurious interrupts and freezes the port when it occurs.
This patch makes it more forgiving.

* On SATA PHY event interrupt, serror value is checked to see whether
  it really is PHYRDY CHG event.  If not, SATA PHY event interrupt is
  ignored.

* If ATA interrupt occurs while no command is in progress, it's
  cleared and ignored.

This fixes bugzilla bug 9505.

  http://bugzilla.kernel.org/show_bug.cgi?id=9505

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

diff --git a/drivers/ata/sata_sil.c b/drivers/ata/sata_sil.c
index 4e6e381279cc657556924c136fca91ac5ebd7284..025622b14efb5dd141ab59e8487221d45205b048 100644 (file)
--- a/drivers/ata/sata_sil.c
+++ b/drivers/ata/sata_sil.c
@@ -390,23 +390,28 @@ static void sil_host_intr(struct ata_port *ap, u32 bmdma2)
                sil_scr_read(ap, SCR_ERROR, &serror);
                sil_scr_write(ap, SCR_ERROR, serror);
 
-               /* Trigger hotplug and accumulate SError only if the
-                * port isn't already frozen.  Otherwise, PHY events
-                * during hardreset makes controllers with broken SIEN
-                * repeat probing needlessly.
+               /* Sometimes spurious interrupts occur, double check
+                * it's PHYRDY CHG.
                 */
-               if (!(ap->pflags & ATA_PFLAG_FROZEN)) {
-                       ata_ehi_hotplugged(&ap->link.eh_info);
-                       ap->link.eh_info.serror |= serror;
+               if (serror & SERR_PHYRDY_CHG) {
+                       /* Trigger hotplug and accumulate SError only
+                        * if the port isn't already frozen.
+                        * Otherwise, PHY events during hardreset
+                        * makes controllers with broken SIEN repeat
+                        * probing needlessly.
+                        */
+                       if (!(ap->pflags & ATA_PFLAG_FROZEN)) {
+                               ata_ehi_hotplugged(&ap->link.eh_info);
+                               ap->link.eh_info.serror |= serror;
+                       }
+                       goto freeze;
                }
 
-               goto freeze;
+               if (!(bmdma2 & SIL_DMA_COMPLETE))
+                       return;
        }
 
-       if (unlikely(!qc))
-               goto freeze;
-
-       if (unlikely(qc->tf.flags & ATA_TFLAG_POLLING)) {
+       if (unlikely(!qc || (qc->tf.flags & ATA_TFLAG_POLLING))) {
                /* this sometimes happens, just clear IRQ */
                ata_chk_status(ap);
                return;