iwlwifi: add debug information on queue stop / wake

Users complain that the traffic gets stalled sometimes. This will
allow easier debugging.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
index 014b98a..e6a02e0 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
@@ -813,7 +813,8 @@
 			    iwl_is_associated_ctx(ctx) && ctx->vif &&
 			    ctx->vif->type == NL80211_IFTYPE_STATION) {
 				ctx->last_tx_rejected = true;
-				iwl_trans_stop_queue(trans(priv), txq_id);
+				iwl_trans_stop_queue(trans(priv), txq_id,
+					"Tx on passive channel");
 
 				IWL_DEBUG_TX_REPLY(priv,
 					   "TXQ %d status %s (0x%08x) "