ixgbe: update {P}FC thresholds to account for X540 and loopback
Revise high and low threshold marks wrt flow control to account
for the X540 devices and latency introduced by the loopback
switch.
Without this it was in theory possible to drop frames on a
supposedly lossless link with X540 or SR-IOV enabled.
Previously we used a magic number in a define to calculate the
threshold values. This made it difficult to sort out exactly
which latencies were or were not being accounted for. Here
I was overly explicit and tried to used #define names that would
be recognizable after reading the IEEE 802.1Qbb specification.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
index 84ed9ef..59cd54c 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
@@ -1932,7 +1932,6 @@
s32 ret_val = 0;
u32 mflcn_reg, fccfg_reg;
u32 reg;
- u32 rx_pba_size;
u32 fcrtl, fcrth;
#ifdef CONFIG_DCB
@@ -2012,11 +2011,8 @@
IXGBE_WRITE_REG(hw, IXGBE_MFLCN, mflcn_reg);
IXGBE_WRITE_REG(hw, IXGBE_FCCFG, fccfg_reg);
- rx_pba_size = IXGBE_READ_REG(hw, IXGBE_RXPBSIZE(packetbuf_num));
- rx_pba_size >>= IXGBE_RXPBSIZE_SHIFT;
-
- fcrth = (rx_pba_size - hw->fc.high_water) << 10;
- fcrtl = (rx_pba_size - hw->fc.low_water) << 10;
+ fcrth = hw->fc.high_water[packetbuf_num] << 10;
+ fcrtl = hw->fc.low_water << 10;
if (hw->fc.current_mode & ixgbe_fc_tx_pause) {
fcrth |= IXGBE_FCRTH_FCEN;
@@ -2293,7 +2289,9 @@
* Validate the water mark configuration. Zero water marks are invalid
* because it causes the controller to just blast out fc packets.
*/
- if (!hw->fc.low_water || !hw->fc.high_water || !hw->fc.pause_time) {
+ if (!hw->fc.low_water ||
+ !hw->fc.high_water[packetbuf_num] ||
+ !hw->fc.pause_time) {
hw_dbg(hw, "Invalid water mark configuration\n");
ret_val = IXGBE_ERR_INVALID_LINK_SETTINGS;
goto out;