igb: defeature tx head writeback
This patch removes tx head writeback as it was found to not provide a
significant improvement in tx performance and on some systems has been seen
to cause a performance degredation due to partial cache line writes.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/igb/e1000_defines.h b/drivers/net/igb/e1000_defines.h
index c5fe784..40d0342 100644
--- a/drivers/net/igb/e1000_defines.h
+++ b/drivers/net/igb/e1000_defines.h
@@ -323,6 +323,7 @@
#define E1000_TXD_CMD_IFCS 0x02000000 /* Insert FCS (Ethernet CRC) */
#define E1000_TXD_CMD_RS 0x08000000 /* Report Status */
#define E1000_TXD_CMD_DEXT 0x20000000 /* Descriptor extension (0 = legacy) */
+#define E1000_TXD_STAT_DD 0x00000001 /* Descriptor Done */
/* Extended desc bits for Linksec and timesync */
/* Transmit Control */