libata: don't consider 0xff as port empty if SStatus is available

Some SATA controllers (sata_sil) use 0xff to indicate port not ready status, not port empty. As libata interprets 0xff as port empty, this causes unnecessary reset failure and retry. Don't consider 0xff as port empty if SStatus is available and indicates that port is online.

---

This one is for 2.6.22. Thanks.

 libata-core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index a6de57e..5788a9d 100644
@@ -3022,7 +3022,7 @@ int ata_wait_ready(struct ata_port *ap,
 
 		if (!(status & ATA_BUSY))
 			return 0;
-		if (status == 0xff)
+		if (!ata_port_online(ap) && status == 0xff)
 			return -ENODEV;
 		if (time_after(now, deadline))
 			return -EBUSY;