iwlagn: reduce off channel reception for 4965

Force use of chains B and C (0x6) for Rx for 4965
Avoid A (0x1) because of its off-channel reception on A-band.

Signed-off-by: Rick Farrington <rickdic@hotmail.com>
Signed-off-by: Ben Cahill <ben.m.cahill@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 17 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index c72a99a9ab36..61788a508971 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -2698,6 +2698,9 @@ static int iwl_mac_config(struct ieee80211_hw *hw, u32 changed)
 
         iwl_set_rate(priv);
 
+        /* call to ensure that 4965 rx_chain is set properly in monitor mode */
+        iwl_set_rxon_chain(priv);
+
         if (memcmp(&priv->active_rxon,
                    &priv->staging_rxon, sizeof(priv->staging_rxon)))
                 iwl_commit_rxon(priv);
diff --git a/drivers/net/wireless/iwlwifi/iwl-commands.h b/drivers/net/wireless/iwlwifi/iwl-commands.h
index 3ced5e5b6823..7571110f5f15 100644
--- a/drivers/net/wireless/iwlwifi/iwl-commands.h
+++ b/drivers/net/wireless/iwlwifi/iwl-commands.h
@@ -563,6 +563,7 @@ enum {
 
 
 #define RXON_RX_CHAIN_DRIVER_FORCE_MSK          cpu_to_le16(0x1 << 0)
+#define RXON_RX_CHAIN_DRIVER_FORCE_POS          (0)
 #define RXON_RX_CHAIN_VALID_MSK                 cpu_to_le16(0x7 << 1)
 #define RXON_RX_CHAIN_VALID_POS                 (1)
 #define RXON_RX_CHAIN_FORCE_SEL_MSK             cpu_to_le16(0x7 << 4)
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.c b/drivers/net/wireless/iwlwifi/iwl-core.c
index ef4a7c54c736..b64377e760e5 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.c
+++ b/drivers/net/wireless/iwlwifi/iwl-core.c
@@ -753,6 +753,19 @@ void iwl_set_rxon_chain(struct iwl_priv *priv)
         rx_chain |= active_rx_cnt << RXON_RX_CHAIN_MIMO_CNT_POS;
         rx_chain |= idle_rx_cnt  << RXON_RX_CHAIN_CNT_POS;
 
+        /* copied from 'iwl_bg_request_scan()' */
+        /* Force use of chains B and C (0x6) for Rx for 4965
+         * Avoid A (0x1) because of its off-channel reception on A-band.
+         * MIMO is not used here, but value is required */
+        if (iwl_is_monitor_mode(priv) &&
+            !(priv->staging_rxon.flags & RXON_FLG_BAND_24G_MSK) &&
+            ((priv->hw_rev & CSR_HW_REV_TYPE_MSK) == CSR_HW_REV_TYPE_4965)) {
+                rx_chain = 0x07 << RXON_RX_CHAIN_VALID_POS;
+                rx_chain |= 0x06 << RXON_RX_CHAIN_FORCE_SEL_POS;
+                rx_chain |= 0x07 << RXON_RX_CHAIN_FORCE_MIMO_SEL_POS;
+                rx_chain |= 0x01 << RXON_RX_CHAIN_DRIVER_FORCE_POS;
+        }
+
         priv->staging_rxon.rx_chain = cpu_to_le16(rx_chain);
 
         if (!is_single && (active_rx_cnt >= IWL_NUM_RX_CHAINS_SINGLE) && is_cam)