libata: improve initialization and legacy handling, take #3

index 0bcf867..d3dd8e6 100644
@@ -3048,6 +3048,7 @@ static void ata_dev_xfermask(struct ata_
 	struct ata_port *ap = dev->ap;
 	struct ata_host_set *hs = ap->host_set;
 	unsigned long xfer_mask;
+	int i;
 
 	/* controller modes available */
 	xfer_mask = ata_pack_xfermask(ap->pio_mask,

@@ -3075,6 +3076,16 @@ static void ata_dev_xfermask(struct ata_
 			       "other device, disabling DMA\n");
 	}
 
+	/* Use the lowest common PIO mode to avoid violating device
+	 * selection timing.
+	 */
+	for (i = 0; i < ATA_MAX_DEVICES; i++) {
+		struct ata_device *d = &ap->device[i];
+		if (!ata_dev_absent(d))
+			xfer_mask &= ata_pack_xfermask(d->pio_mask,
+						       UINT_MAX, UINT_MAX);
+	}
+
 	if (ap->ops->mode_filter)
 		xfer_mask = ap->ops->mode_filter(ap, dev, xfer_mask);