From ea196fdbb982150c19854f90773cb8b9bf331049 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 3 Sep 2010 06:30:55 -0700 Subject: [PATCH] iwlwifi: fix and describe iwl_adjust_beacon_interval The iwl_adjust_beacon_interval function is a bit of black magic, so add comments to it describing what it does. Also, in the case when there's no beacon interval set, program the default into the device (instead of adjusting, which results in the max) since using the max in that case interacts badly with dual-mode/PAN parameters. Also update the PAN parameters accordingly and use the same constant as here. Signed-off-by: Johannes Berg Signed-off-by: Wey-Yi Guy --- drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c | 4 ++-- drivers/net/wireless/iwlwifi/iwl-core.c | 25 +++++++++++++++++++-- 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;