diff --git a/drivers/ata/pata_serverworks.c b/drivers/ata/pata_serverworks.c
index 2c0bc3b..0231aba 100644
--- a/drivers/ata/pata_serverworks.c
+++ b/drivers/ata/pata_serverworks.c
@@ -495,14 +495,14 @@
 			.flags = ATA_FLAG_SLAVE_POSS,
 			.pio_mask = 0x1f,
 			.mwdma_mask = 0x07,
-			.udma_mask = 0x1f,
+			.udma_mask = ATA_UDMA4,
 			.port_ops = &serverworks_csb_port_ops
 		}, { /* CSB5 - later revisions*/
 			.sht = &serverworks_sht,
 			.flags = ATA_FLAG_SLAVE_POSS,
 			.pio_mask = 0x1f,
 			.mwdma_mask = 0x07,
-			.udma_mask = 0x3f,
+			.udma_mask = ATA_UDMA5,
 			.port_ops = &serverworks_csb_port_ops
 		}
 	};