[PATCH] ipw2200: Enables the "slow diversity" algorithm

This forces one antenna or the other, if the background noise is
significantly quieter in one than the other. It favors the quieter
antenna, and won't kick in unless the difference is significant.
Signed-off-by: NCahill, Ben M <ben.m.cahill@intel.com>
Signed-off-by: NZhu Yi <yi.zhu@intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ipw2200.c

@@ -9600,7 +9600,7 @@ static  void init_sys_config(struct ipw_sys_config *sys_config)
 	sys_config->disable_unicast_decryption = 1;
 	sys_config->exclude_multicast_unencrypted = 0;
 	sys_config->disable_multicast_decryption = 1;
-	sys_config->antenna_diversity = CFG_SYS_ANTENNA_BOTH;
+	sys_config->antenna_diversity = CFG_SYS_ANTENNA_SLOW_DIV;
 	sys_config->pass_crc_to_host = 0;	/* TODO: See if 1 gives us FCS */
 	sys_config->dot11g_auto_detection = 0;
 	sys_config->enable_cts_to_self = 0;

drivers/net/wireless/ipw2200.h

@@ -1895,6 +1895,7 @@ struct ipw_cmd_log {
 #define CFG_SYS_ANTENNA_BOTH            0x00	/* NIC selects best antenna */
 #define CFG_SYS_ANTENNA_A               0x01	/* force antenna A */
 #define CFG_SYS_ANTENNA_B               0x03	/* force antenna B */
+#define CFG_SYS_ANTENNA_SLOW_DIV        0x02	/* consider background noise */
 
 /*
  * The definitions below were lifted off the ipw2100 driver, which only