iwlwifi: avoid sending too many commands

When the PAN context is unused, there's no
need to continually update it in the device.
So track which contexts are active (with the
special case that the WLAN context is always
active ...) and only send their commands to
the device when needed.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c b/drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c
index d03ba6a..a63582f 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c
@@ -287,6 +287,15 @@
 	ctx_bss = &priv->contexts[IWL_RXON_CTX_BSS];
 	ctx_pan = &priv->contexts[IWL_RXON_CTX_PAN];
 
+	/*
+	 * If the PAN context is inactive, then we don't need
+	 * to update the PAN parameters, the last thing we'll
+	 * have done before it goes inactive is making the PAN
+	 * parameters be WLAN-only.
+	 */
+	if (!ctx_pan->is_active)
+		return 0;
+
 	memset(&cmd, 0, sizeof(cmd));
 
 	/* only 2 slots are currently allowed */