diff --git a/drivers/ata/pata_winbond.c b/drivers/ata/pata_winbond.c
index 319e164..6d8619b 100644
--- a/drivers/ata/pata_winbond.c
+++ b/drivers/ata/pata_winbond.c
@@ -193,7 +193,7 @@
 		ata_port_desc(ap, "cmd 0x%lx ctl 0x%lx", cmd_port, ctl_port);
 
 		ap->ops = &winbond_port_ops;
-		ap->pio_mask = 0x1F;
+		ap->pio_mask = ATA_PIO4;
 		ap->flags |= ATA_FLAG_SLAVE_POSS;
 		ap->ioaddr.cmd_addr = cmd_addr;
 		ap->ioaddr.altstatus_addr = ctl_addr;