e1000: omit stats for broken counter in 82543

The 82543 chip does not count tx_carrier_errors properly in FD mode;
report zeros instead of garbage.

Originally from Jesse Brandeburg <jesse.brandeburg@intel.com>, rewritten
to use feature flags by me.

Signed-off-by: Jeff Garzik <jeff@garzik.org>

3 files changed, 12 insertions, 0 deletions

diff --git a/drivers/net/e1000/e1000_hw.c b/drivers/net/e1000/e1000_hw.c
index 0201ca548cd1..ce82eb52ea95 100644
--- a/drivers/net/e1000/e1000_hw.c
+++ b/drivers/net/e1000/e1000_hw.c
@@ -442,6 +442,12 @@ e1000_set_mac_type(struct e1000_hw *hw)
                 break;
         }
 
+        /* The 82543 chip does not count tx_carrier_errors properly in
+         * FD mode
+         */
+        if (hw->mac_type == e1000_82543)
+                hw->bad_tx_carr_stats_fd = TRUE;
+
         return E1000_SUCCESS;
 }
 
diff --git a/drivers/net/e1000/e1000_hw.h b/drivers/net/e1000/e1000_hw.h
index 28cdfe39e39a..fef1f7b4845b 100644
--- a/drivers/net/e1000/e1000_hw.h
+++ b/drivers/net/e1000/e1000_hw.h
@@ -1460,6 +1460,7 @@ struct e1000_hw {
         boolean_t               mng_reg_access_disabled;
         boolean_t               leave_av_bit_off;
         boolean_t               kmrn_lock_loss_workaround_disabled;
+        boolean_t               bad_tx_carr_stats_fd;
 };
 
 
diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index 62ef267b3d64..0816de267610 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -3581,6 +3581,11 @@ e1000_update_stats(struct e1000_adapter *adapter)
         adapter->net_stats.tx_aborted_errors = adapter->stats.ecol;
         adapter->net_stats.tx_window_errors = adapter->stats.latecol;
         adapter->net_stats.tx_carrier_errors = adapter->stats.tncrs;
+        if (adapter->hw.bad_tx_carr_stats_fd &&
+            adapter->link_duplex == FULL_DUPLEX) {
+                adapter->net_stats.tx_carrier_errors = 0;
+                adapter->stats.tncrs = 0;
+        }
 
         /* Tx Dropped needs to be maintained elsewhere */