e1000e: Set InterruptThrottleRate to default when invalid value used

During module load, seting the InterruptThrottleRate parameter to an
invalid value would result in the itr/itr_setting pair being set to
unexpected values which would result in poor performance.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 19 insertions, 4 deletions

diff --git a/drivers/net/e1000e/param.c b/drivers/net/e1000e/param.c
index 8effc3107f9a..b0499f27e5ff 100644
--- a/drivers/net/e1000e/param.c
+++ b/drivers/net/e1000e/param.c
@@ -327,11 +327,26 @@ void __devinit e1000e_check_options(struct e1000_adapter *adapter)
                                 e1000_validate_option(&adapter->itr, &opt,
                                         adapter);
                                 /*
-                                 * save the setting, because the dynamic bits
-                                 * change itr. clear the lower two bits
-                                 * because they are used as control
+                                 * Save the setting, because the dynamic bits
+                                 * change itr.
                                  */
-                                adapter->itr_setting = adapter->itr & ~3;
+                                if (e1000_validate_option(&adapter->itr, &opt,
+                                                          adapter) &&
+                                    (adapter->itr == 3)) {
+                                        /*
+                                         * In case of invalid user value,
+                                         * default to conservative mode.
+                                         */
+                                        adapter->itr_setting = adapter->itr;
+                                        adapter->itr = 20000;
+                                } else {
+                                        /*
+                                         * Clear the lower two bits because
+                                         * they are used as control.
+                                         */
+                                        adapter->itr_setting =
+                                                adapter->itr & ~3;
+                                }
                                 break;
                         }
                 } else {