iwlwifi: do not schedule tasklet when rcv unused irq

The nic controller's scheduler interrupt (CSR_INT_BIT_SCD) indicates
to the driver that scheduler finished to transmit the frame/frames.
This bit is not used and the tasklet should thus not be scheduled upon
its receipt.

Signed-off-by: Joonwoo Park <joonwpark81@gmail.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index 8cef48c9d748..f644c6bba85f 100644
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -4759,8 +4759,9 @@ static void iwl3945_irq_tasklet(struct iwl3945_priv *priv)
 #ifdef CONFIG_IWL3945_DEBUG
         if (iwl3945_debug_level & (IWL_DL_ISR)) {
                 /* NIC fires this, but we don't use it, redundant with WAKEUP */
-                if (inta & CSR_INT_BIT_MAC_CLK_ACTV)
-                        IWL_DEBUG_ISR("Microcode started or stopped.\n");
+                if (inta & CSR_INT_BIT_SCD)
+                        IWL_DEBUG_ISR("Scheduler finished to transmit "
+                                      "the frame/frames.\n");
 
                 /* Alive notification via Rx interrupt will do the real work */
                 if (inta & CSR_INT_BIT_ALIVE)
@@ -4768,7 +4769,7 @@ static void iwl3945_irq_tasklet(struct iwl3945_priv *priv)
         }
 #endif
         /* Safely ignore these bits for debug checks below */
-        inta &= ~(CSR_INT_BIT_MAC_CLK_ACTV | CSR_INT_BIT_ALIVE);
+        inta &= ~(CSR_INT_BIT_SCD | CSR_INT_BIT_ALIVE);
 
         /* HW RF KILL switch toggled (4965 only) */
         if (inta & CSR_INT_BIT_RF_KILL) {
@@ -4904,8 +4905,11 @@ static irqreturn_t iwl3945_isr(int irq, void *data)
         IWL_DEBUG_ISR("ISR inta 0x%08x, enabled 0x%08x, fh 0x%08x\n",
                       inta, inta_mask, inta_fh);
 
+        inta &= ~CSR_INT_BIT_SCD;
+
         /* iwl3945_irq_tasklet() will service interrupts and re-enable them */
-        tasklet_schedule(&priv->irq_tasklet);
+        if (likely(inta || inta_fh))
+                tasklet_schedule(&priv->irq_tasklet);
 unplugged:
         spin_unlock(&priv->lock);