[libata sata_mv] handle lack of hardware nIEN support

Handle errata (it was unintentional on this h/w, whereas its intentional
on others) whereby the nIEN bit in Device Control is ignored, leading to
a situation where a hardware interrupt completes the qc before the
polling code has a chance to.

This will get fixed The Right Way(tm) once Albert Lee's irq-pio
branch is merged, as the more natural PIO method on this hardware is
interrupt-driven.

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/scsi/sata_mv.c b/drivers/scsi/sata_mv.c
index ee0634da087..ac184e60797 100644
--- a/drivers/scsi/sata_mv.c
+++ b/drivers/scsi/sata_mv.c
@@ -1219,6 +1219,10 @@ static void mv_host_intr(struct ata_host_set *host_set, u32 relevant,
                         handled++;
                 }
 
+                if (ap &&
+                    (ap->flags & (ATA_FLAG_PORT_DISABLED | ATA_FLAG_NOINTR)))
+                        continue;
+
                 err_mask = ac_err_mask(ata_status);
 
                 shift = port << 1;              /* (port * 2) */
@@ -1237,7 +1241,8 @@ static void mv_host_intr(struct ata_host_set *host_set, u32 relevant,
                                 VPRINTK("port %u IRQ found for qc, "
                                         "ata_status 0x%x\n", port,ata_status);
                                 /* mark qc status appropriately */
-                                ata_qc_complete(qc, err_mask);
+                                if (!(qc->tf.ctl & ATA_NIEN))
+                                        ata_qc_complete(qc, err_mask);
                         }
                 }
         }