1 files changed, 12 insertions, 4 deletions

diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c
index ef83e6b1e314..233e88693395 100644
--- a/drivers/ata/sata_sil24.c
+++ b/drivers/ata/sata_sil24.c
@@ -888,6 +888,16 @@ static inline void sil24_host_intr(struct ata_port *ap)
         u32 slot_stat, qc_active;
         int rc;
 
+        /* If PCIX_IRQ_WOC, there's an inherent race window between
+         * clearing IRQ pending status and reading PORT_SLOT_STAT
+         * which may cause spurious interrupts afterwards.  This is
+         * unavoidable and much better than losing interrupts which
+         * happens if IRQ pending is cleared after reading
+         * PORT_SLOT_STAT.
+         */
+        if (ap->flags & SIL24_FLAG_PCIX_IRQ_WOC)
+                writel(PORT_IRQ_COMPLETE, port + PORT_IRQ_STAT);
+
         slot_stat = readl(port + PORT_SLOT_STAT);
 
         if (unlikely(slot_stat & HOST_SSTAT_ATTN)) {
@@ -895,9 +905,6 @@ static inline void sil24_host_intr(struct ata_port *ap)
                 return;
         }
 
-        if (ap->flags & SIL24_FLAG_PCIX_IRQ_WOC)
-                writel(PORT_IRQ_COMPLETE, port + PORT_IRQ_STAT);
-
         qc_active = slot_stat & ~HOST_SSTAT_ATTN;
         rc = ata_qc_complete_multiple(ap, qc_active, sil24_finish_qc);
         if (rc > 0)
@@ -910,7 +917,8 @@ static inline void sil24_host_intr(struct ata_port *ap)
                 return;
         }
 
-        if (ata_ratelimit())
+        /* spurious interrupts are expected if PCIX_IRQ_WOC */
+        if (!(ap->flags & SIL24_FLAG_PCIX_IRQ_WOC) && ata_ratelimit())
                 ata_port_printk(ap, KERN_INFO, "spurious interrupt "
                         "(slot_stat 0x%x active_tag %d sactive 0x%x)\n",
                         slot_stat, ap->active_tag, ap->sactive);