ixgbe: disable flow control by default

Since the adapter cannot tell what the remote end's flow control capability
is through auto-neg, we must turn off flow control by default.
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/ixgbe/ixgbe.h

@@ -69,12 +69,12 @@
 
 /* flow control */
 #define IXGBE_DEFAULT_FCRTL		0x10000
-#define IXGBE_MIN_FCRTL			      0
+#define IXGBE_MIN_FCRTL			   0x40
 #define IXGBE_MAX_FCRTL			0x7FF80
 #define IXGBE_DEFAULT_FCRTH		0x20000
-#define IXGBE_MIN_FCRTH			      0
+#define IXGBE_MIN_FCRTH			  0x600
 #define IXGBE_MAX_FCRTH			0x7FFF0
-#define IXGBE_DEFAULT_FCPAUSE		 0x6800  /* may be too long */
+#define IXGBE_DEFAULT_FCPAUSE		 0xFFFF
 #define IXGBE_MIN_FCPAUSE		      0
 #define IXGBE_MAX_FCPAUSE		 0xFFFF
 

drivers/net/ixgbe/ixgbe_common.c

@@ -1064,6 +1064,13 @@ s32 ixgbe_setup_fc(struct ixgbe_hw *hw, s32 packetbuf_num)
 	rmcs_reg = IXGBE_READ_REG(hw, IXGBE_RMCS);
 	rmcs_reg &= ~(IXGBE_RMCS_TFCE_PRIORITY | IXGBE_RMCS_TFCE_802_3X);
 
+	/*
+	 * 10 gig parts do not have a word in the EEPROM to determine the
+	 * default flow control setting, so we explicitly set it to full.
+	 */
+	if (hw->fc.type == ixgbe_fc_default)
+		hw->fc.type = ixgbe_fc_full;
+
 	/*
 	 * We want to save off the original Flow Control configuration just in
 	 * case we get disconnected and then reconnected into a different hub
@@ -1116,6 +1123,16 @@ s32 ixgbe_setup_fc(struct ixgbe_hw *hw, s32 packetbuf_num)
 	IXGBE_WRITE_REG(hw, IXGBE_FCTRL, frctl_reg);
 	IXGBE_WRITE_REG(hw, IXGBE_RMCS, rmcs_reg);
 
+	/*
+	 * Check for invalid software configuration, zeros are completely
+	 * invalid for all parameters used past this point, and if we enable
+	 * flow control with zero water marks, we blast flow control packets.
+	 */
+	if (!hw->fc.low_water || !hw->fc.high_water || !hw->fc.pause_time) {
+		hw_dbg(hw, "Flow control structure initialized incorrectly\n");
+		return IXGBE_ERR_INVALID_LINK_SETTINGS;
+	}
+
 	/*
 	 * We need to set up the Receive Threshold high and low water
 	 * marks as well as (optionally) enabling the transmission of

drivers/net/ixgbe/ixgbe_main.c

@@ -2446,8 +2446,12 @@ static int __devinit ixgbe_sw_init(struct ixgbe_adapter *adapter)
 	adapter->tx_eitr = 1;
 
 	/* default flow control settings */
-	hw->fc.original_type = ixgbe_fc_full;
-	hw->fc.type = ixgbe_fc_full;
+	hw->fc.original_type = ixgbe_fc_none;
+	hw->fc.type = ixgbe_fc_none;
+	hw->fc.high_water = IXGBE_DEFAULT_FCRTH;
+	hw->fc.low_water = IXGBE_DEFAULT_FCRTL;
+	hw->fc.pause_time = IXGBE_DEFAULT_FCPAUSE;
+	hw->fc.send_xon = true;
 
 	/* select 10G link by default */
 	hw->mac.link_mode_select = IXGBE_AUTOC_LMS_10G_LINK_NO_AN;
@@ -3587,13 +3591,6 @@ static int __devinit ixgbe_probe(struct pci_dev *pdev,
 
 	INIT_WORK(&adapter->reset_task, ixgbe_reset_task);
 
-	/* initialize default flow control settings */
-	hw->fc.original_type = ixgbe_fc_full;
-	hw->fc.type = ixgbe_fc_full;
-	hw->fc.high_water = IXGBE_DEFAULT_FCRTH;
-	hw->fc.low_water = IXGBE_DEFAULT_FCRTL;
-	hw->fc.pause_time = IXGBE_DEFAULT_FCPAUSE;
-
 	err = ixgbe_init_interrupt_scheme(adapter);
 	if (err)
 		goto err_sw_init;