iwlagn: default to MAX_UCODE_BEACON_INTERVAL in iwl_adjust_beacon_interval

Default to MAX_UCODE_BEACON_INTERVAL if the output of
iwl_adjust_beacon_interval would otherwise be zero.  This prevents a
division by zero on my iwl5300-equipped Lenovo T400 with kernels that
include "mac80211: use cfg80211s BSS infrastructure".

This patch is a bit of a hack -- I'm not sure why iwl_setup_rxon_timing
is giving iwl_adjust_beacon_interval a zero input (which is the only way
it would output zero).  I would be happy to have a better fix.  But for
now, this makes my box boot...

Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 50f8c7f47061..ad310050e298 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -644,6 +644,9 @@ static u16 iwl_adjust_beacon_interval(u16 beacon_val)
                                         / MAX_UCODE_BEACON_INTERVAL;
         new_val = beacon_val / beacon_factor;
 
+        if (!new_val)
+                new_val = MAX_UCODE_BEACON_INTERVAL;
+
         return new_val;
 }