diff --git a/drivers/net/cassini.c b/drivers/net/cassini.c
index 521c5b7..fd2cc13 100644
--- a/drivers/net/cassini.c
+++ b/drivers/net/cassini.c
@@ -2825,7 +2825,7 @@
 		u64 csum_start_off, csum_stuff_off;
 
 		csum_start_off = (u64) (skb->h.raw - skb->data);
-		csum_stuff_off = (u64) ((skb->h.raw + skb->csum) - skb->data);
+		csum_stuff_off = csum_start_off + skb->csum_offset;
 
 		ctrl =  TX_DESC_CSUM_EN |
 			CAS_BASE(TX_DESC_CSUM_START, csum_start_off) |