ixgbe: fix bug when EITR=0 causing no writebacks
writebacks can be held indefinitely by hardware if EITR=0, when
combined with TXDCTL.WTHRESH=8. When EITR=0, WTHRESH should be
set back to zero.
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@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/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
index 0c4ca68..fe7e260 100644
--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c
@@ -2945,8 +2945,13 @@
for (i = 0; i < adapter->num_tx_queues; i++) {
j = adapter->tx_ring[i]->reg_idx;
txdctl = IXGBE_READ_REG(hw, IXGBE_TXDCTL(j));
- /* enable WTHRESH=8 descriptors, to encourage burst writeback */
- txdctl |= (8 << 16);
+ if (adapter->rx_itr_setting == 0) {
+ /* cannot set wthresh when itr==0 */
+ txdctl &= ~0x007F0000;
+ } else {
+ /* enable WTHRESH=8 descriptors, to encourage burst writeback */
+ txdctl |= (8 << 16);
+ }
IXGBE_WRITE_REG(hw, IXGBE_TXDCTL(j), txdctl);
}