iwlwifi: eliminate the possible 1/2 dBm tx power loss in 6x00 & 6x50 series

In both 6x00 and 6x50 series, the enhanced/extended tx power table in
EEPROM is used to set the max. tx power limit.
This new tx power table is in 1/2 dBm format, which creates an issue of
possibility of 1/2 dBm loss when driver set the tx power limit; because
of driver keep track and report the tx power in dBm format.

In order to prevent the 1/2 dBm loss, keep track of the true max tx
power in 1/2 dBm format in driver; do the comparison and adjust the tx
power if needed when send tx power command to uCode.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/iwlwifi/iwl-5000.c b/drivers/net/wireless/iwlwifi/iwl-5000.c
index 6eaf26b..48982fb 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-5000.c
+++ b/drivers/net/wireless/iwlwifi/iwl-5000.c
@@ -1250,6 +1250,22 @@ int  iwl5000_send_tx_power(struct iwl_priv *priv)
 
        /* half dBm need to multiply */
        tx_power_cmd.global_lmt = (s8)(2 * priv->tx_power_user_lmt);
+
+       if (priv->tx_power_lmt_in_half_dbm &&
+           priv->tx_power_lmt_in_half_dbm < tx_power_cmd.global_lmt) {
+               /*
+                * For the newer devices which using enhanced/extend tx power
+                * table in EEPROM, the format is in half dBm. driver need to
+                * convert to dBm format before report to mac80211.
+                * By doing so, there is a possibility of 1/2 dBm resolution
+                * lost. driver will perform "round-up" operation before
+                * reporting, but it will cause 1/2 dBm tx power over the
+                * regulatory limit. Perform the checking here, if the
+                * "tx_power_user_lmt" is higher than EEPROM value (in
+                * half-dBm format), lower the tx power based on EEPROM
+                */
+               tx_power_cmd.global_lmt = priv->tx_power_lmt_in_half_dbm;
+       }
        tx_power_cmd.flags = IWL50_TX_POWER_NO_CLOSED;
        tx_power_cmd.srv_chan_lmt = IWL50_TX_POWER_AUTO;
 

diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 774a315..a474383 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -1247,6 +1247,7 @@ struct iwl_priv {
        /* TX Power */
        s8 tx_power_user_lmt;
        s8 tx_power_device_lmt;
+       s8 tx_power_lmt_in_half_dbm; /* max tx power in half-dBm format */
 
 
 #ifdef CONFIG_IWLWIFI_DEBUG

diff --git a/drivers/net/wireless/iwlwifi/iwl-eeprom.c b/drivers/net/wireless/iwlwifi/iwl-eeprom.c
index e42eb64..ac88ff0 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-eeprom.c
+++ b/drivers/net/wireless/iwlwifi/iwl-eeprom.c
@@ -762,7 +762,8 @@ static int iwl_mod_ht40_chan_info(struct iwl_priv *priv,
  *     find the highest tx power from all chains for the channel
  */
 static s8 iwl_get_max_txpower_avg(struct iwl_priv *priv,
-               struct iwl_eeprom_enhanced_txpwr *enhanced_txpower, int element)
+               struct iwl_eeprom_enhanced_txpwr *enhanced_txpower,
+               int element, s8 *max_txpower_in_half_dbm)
 {
        s8 max_txpower_avg = 0; /* (dBm) */
 
@@ -794,10 +795,14 @@ static s8 iwl_get_max_txpower_avg(struct iwl_priv *priv,
            (enhanced_txpower[element].mimo3_max > max_txpower_avg))
                max_txpower_avg = enhanced_txpower[element].mimo3_max;
 
-       /* max. tx power in EEPROM is in 1/2 dBm format
-        * convert from 1/2 dBm to dBm
+       /*
+        * max. tx power in EEPROM is in 1/2 dBm format
+        * convert from 1/2 dBm to dBm (round-up convert)
+        * but we also do not want to loss 1/2 dBm resolution which
+        * will impact performance
         */
-       return max_txpower_avg >> 1;
+       *max_txpower_in_half_dbm = max_txpower_avg;
+       return (max_txpower_avg & 0x01) + (max_txpower_avg >> 1);
 }
 
 /**
@@ -806,7 +811,7 @@ static s8 iwl_get_max_txpower_avg(struct iwl_priv *priv,
  */
 static s8 iwl_update_common_txpower(struct iwl_priv *priv,
                struct iwl_eeprom_enhanced_txpwr *enhanced_txpower,
-               int section, int element)
+               int section, int element, s8 *max_txpower_in_half_dbm)
 {
        struct iwl_channel_info *ch_info;
        int ch;
@@ -820,20 +825,22 @@ static s8 iwl_update_common_txpower(struct iwl_priv *priv,
        if (element == EEPROM_TXPOWER_COMMON_HT40_INDEX)
                is_ht40 = true;
        max_txpower_avg =
-               iwl_get_max_txpower_avg(priv, enhanced_txpower, element);
+               iwl_get_max_txpower_avg(priv, enhanced_txpower,
+                                       element, max_txpower_in_half_dbm);
+
        ch_info = priv->channel_info;
 
        for (ch = 0; ch < priv->channel_count; ch++) {
                /* find matching band and update tx power if needed */
                if ((ch_info->band == enhinfo[section].band) &&
-                   (ch_info->max_power_avg < max_txpower_avg) && (!is_ht40)) {
+                   (ch_info->max_power_avg < max_txpower_avg) &&
+                   (!is_ht40)) {
                        /* Update regulatory-based run-time data */
                        ch_info->max_power_avg = ch_info->curr_txpow =
-                           max_txpower_avg;
+                               max_txpower_avg;
                        ch_info->scan_power = max_txpower_avg;
                }
                if ((ch_info->band == enhinfo[section].band) && is_ht40 &&
-                   ch_info->ht40_max_power_avg &&
                    (ch_info->ht40_max_power_avg < max_txpower_avg)) {
                        /* Update regulatory-based run-time data */
                        ch_info->ht40_max_power_avg = max_txpower_avg;
@@ -849,7 +856,7 @@ static s8 iwl_update_common_txpower(struct iwl_priv *priv,
  */
 static s8 iwl_update_channel_txpower(struct iwl_priv *priv,
                struct iwl_eeprom_enhanced_txpwr *enhanced_txpower,
-               int section, int element)
+               int section, int element, s8 *max_txpower_in_half_dbm)
 {
        struct iwl_channel_info *ch_info;
        int ch;
@@ -858,7 +865,8 @@ static s8 iwl_update_channel_txpower(struct iwl_priv *priv,
 
        channel = enhinfo[section].iwl_eeprom_section_channel[element];
        max_txpower_avg =
-               iwl_get_max_txpower_avg(priv, enhanced_txpower, element);
+               iwl_get_max_txpower_avg(priv, enhanced_txpower,
+                                       element, max_txpower_in_half_dbm);
 
        ch_info = priv->channel_info;
        for (ch = 0; ch < priv->channel_count; ch++) {
@@ -872,7 +880,6 @@ static s8 iwl_update_channel_txpower(struct iwl_priv *priv,
                                ch_info->scan_power = max_txpower_avg;
                        }
                        if ((enhinfo[section].is_ht40) &&
-                           (ch_info->ht40_max_power_avg) &&
                            (ch_info->ht40_max_power_avg < max_txpower_avg)) {
                                /* Update regulatory-based run-time data */
                                ch_info->ht40_max_power_avg = max_txpower_avg;
@@ -894,6 +901,7 @@ void iwlcore_eeprom_enhanced_txpower(struct iwl_priv *priv)
        struct iwl_eeprom_enhanced_txpwr *enhanced_txpower;
        u32 offset;
        s8 max_txpower_avg; /* (dBm) */
+       s8 max_txpower_in_half_dbm; /* (half-dBm) */
 
        /* Loop through all the sections
         * adjust bands and channel's max tx power
@@ -920,16 +928,29 @@ void iwlcore_eeprom_enhanced_txpower(struct iwl_priv *priv)
                        if (enhinfo[section].is_common)
                                max_txpower_avg =
                                        iwl_update_common_txpower(priv,
-                                       enhanced_txpower, section, element);
+                                               enhanced_txpower, section,
+                                               element,
+                                               &max_txpower_in_half_dbm);
                        else
                                max_txpower_avg =
                                        iwl_update_channel_txpower(priv,
-                                       enhanced_txpower, section, element);
+                                               enhanced_txpower, section,
+                                               element,
+                                               &max_txpower_in_half_dbm);
 
                        /* Update the tx_power_user_lmt to the highest power
                         * supported by any channel */
                        if (max_txpower_avg > priv->tx_power_user_lmt)
                                priv->tx_power_user_lmt = max_txpower_avg;
+
+                       /*
+                        * Update the tx_power_lmt_in_half_dbm to
+                        * the highest power supported by any channel
+                        */
+                       if (max_txpower_in_half_dbm >
+                           priv->tx_power_lmt_in_half_dbm)
+                               priv->tx_power_lmt_in_half_dbm =
+                                       max_txpower_in_half_dbm;
                }
        }
 }