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>

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);

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)

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)