iwlwifi: error checking for setting tx_power in sysfs

Perform error checking and report failure when setting tx power from
sysfs.
If fail to set the tx power, do not update the local copy, so user will
not see the incorrect tx power in sysfs

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>

1 files changed, 9 insertions, 4 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 2232b1794e76..533b393e8cf6 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -2477,10 +2477,15 @@ static ssize_t store_tx_power(struct device *d,
         ret = strict_strtoul(buf, 10, &val);
         if (ret)
                 IWL_INFO(priv, "%s is not in decimal form.\n", buf);
-        else
-                iwl_set_tx_power(priv, val, false);
-
-        return count;
+        else {
+                ret = iwl_set_tx_power(priv, val, false);
+                if (ret)
+                        IWL_ERR(priv, "failed setting tx power (0x%d).\n",
+                                ret);
+                else
+                        ret = count;
+        }
+        return ret;
 }
 
 static DEVICE_ATTR(tx_power, S_IWUSR | S_IRUGO, show_tx_power, store_tx_power);