ide: don't enable IORDY at a probe time

* Add 'unsigned long port_flags' field to ide_hwif_t.

* Add IDE_PFLAG_PROBING port flag and keep it set during probing.

* Fix ide_pio_need_iordy() to not enable IORDY at a probe time
  (IORDY may lead to controller lock up on certain controllers
   if the port is not occupied).

Loosely based on the recent libata's fix by Tejun, thanks to Alan
for the hint that IDE may also need it.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-probe.c

@@ -1378,6 +1378,9 @@ int ide_host_register(struct ide_host *host, const struct ide_port_info *d,
 
 		ide_init_port(hwif, i & 1, d);
 		ide_port_cable_detect(hwif);
+
+		hwif->port_flags |= IDE_PFLAG_PROBING;
+
 		ide_port_init_devices(hwif);
 	}
 
@@ -1388,6 +1391,8 @@ int ide_host_register(struct ide_host *host, const struct ide_port_info *d,
 		if (ide_probe_port(hwif) == 0)
 			hwif->present = 1;
 
+		hwif->port_flags &= ~IDE_PFLAG_PROBING;
+
 		if ((hwif->host_flags & IDE_HFLAG_4DRIVES) == 0 ||
 		    hwif->mate == NULL || hwif->mate->present == 0) {
 			if (ide_register_port(hwif)) {
@@ -1569,11 +1574,20 @@ EXPORT_SYMBOL_GPL(ide_host_remove);
 
 void ide_port_scan(ide_hwif_t *hwif)
 {
+	int rc;
+
 	ide_port_apply_params(hwif);
 	ide_port_cable_detect(hwif);
+
+	hwif->port_flags |= IDE_PFLAG_PROBING;
+
 	ide_port_init_devices(hwif);
 
-	if (ide_probe_port(hwif) < 0)
+	rc = ide_probe_port(hwif);
+
+	hwif->port_flags &= ~IDE_PFLAG_PROBING;
+
+	if (rc < 0)
 		return;
 
 	hwif->present = 1;