2 files changed, 25 insertions, 4 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c b/drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c
index a63582f060f1..d86902b83630 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c
@@ -321,7 +321,7 @@ static int iwlagn_set_pan_params(struct iwl_priv *priv)
                         bcnint = max_t(int, bcnint,
                                        ctx_bss->vif->bss_conf.beacon_int);
                 if (!bcnint)
-                        bcnint = 100;
+                        bcnint = DEFAULT_BEACON_INTERVAL;
                 slot0 = bcnint / 2;
                 slot1 = bcnint - slot0;
 
@@ -339,7 +339,7 @@ static int iwlagn_set_pan_params(struct iwl_priv *priv)
                 slot0 = 0;
                 slot1 = max_t(int, 1, ctx_pan->vif->bss_conf.dtim_period) *
                                         ctx_pan->vif->bss_conf.beacon_int;
-                slot1 = max_t(int, 100, slot1);
+                slot1 = max_t(int, DEFAULT_BEACON_INTERVAL, slot1);
 
                 if (test_bit(STATUS_SCAN_HW, &priv->status)) {
                         slot0 = slot1 * 3 - 20;
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.c b/drivers/net/wireless/iwlwifi/iwl-core.c
index c393b20ae1c1..c9c523b2883f 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.c
+++ b/drivers/net/wireless/iwlwifi/iwl-core.c
@@ -491,8 +491,29 @@ EXPORT_SYMBOL(iwl_is_ht40_tx_allowed);
 
 static u16 iwl_adjust_beacon_interval(u16 beacon_val, u16 max_beacon_val)
 {
-        u16 new_val = 0;
-        u16 beacon_factor = 0;
+        u16 new_val;
+        u16 beacon_factor;
+
+        /*
+         * If mac80211 hasn't given us a beacon interval, program
+         * the default into the device (not checking this here
+         * would cause the adjustment below to return the maximum
+         * value, which may break PAN.)
+         */
+        if (!beacon_val)
+                return DEFAULT_BEACON_INTERVAL;
+
+        /*
+         * If the beacon interval we obtained from the peer
+         * is too large, we'll have to wake up more often
+         * (and in IBSS case, we'll beacon too much)
+         *
+         * For example, if max_beacon_val is 4096, and the
+         * requested beacon interval is 7000, we'll have to
+         * use 3500 to be able to wake up on the beacons.
+         *
+         * This could badly influence beacon detection stats.
+         */
 
         beacon_factor = (beacon_val + max_beacon_val) / max_beacon_val;
         new_val = beacon_val / beacon_factor;