Patch "iwlwifi: mvm: don't use transmit queue hang detection when it is not possible" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

iwlwifi: mvm: don't use transmit queue hang detection when it is not possible

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
iwlwifi-mvm-don-t-use-transmit-queue-hang-detection-when-it-is-not-possible.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Emmanuel Grumbach <[email protected]>
Date: Mon, 13 Nov 2017 09:50:47 +0200
Subject: iwlwifi: mvm: don't use transmit queue hang detection when it is not possible

From: Emmanuel Grumbach <[email protected]>

commit 0b9832b712d6767d6c7b01965fd788d1ca84fc92 upstream.

When we act as an AP, new firmware versions handle internally the power saving clients and the driver doesn't know that the peers went to sleep. It is, hence, possible that a peer goes to sleep for a long time and stop pulling frames. This will cause its transmit queue to hang which is a condition that triggers the recovery flow in the driver.

While this client is certainly buggy (it should have pulled the frame based on the TIM IE in the beacon), we can't blow up because of a buggy client.

Change the current implementation to not enable the transmit queue hang detection on queues that serve peers when we act as an AP / GO.

We can still enable this mechanism using the debug configuration which can come in handy when we want to debug why the client doesn't wake up.

---
 drivers/net/wireless/intel/iwlwifi/mvm/utils.c |   11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

@@ -1143,9 +1143,18 @@ unsigned int iwl_mvm_get_wd_timeout(stru
 	unsigned int default_timeout =
 		cmd_q ? IWL_DEF_WD_TIMEOUT : mvm->cfg->base_params->wd_timeout;
 
-	if (!iwl_fw_dbg_trigger_enabled(mvm->fw, FW_DBG_TRIGGER_TXQ_TIMERS))
+	if (!iwl_fw_dbg_trigger_enabled(mvm->fw, FW_DBG_TRIGGER_TXQ_TIMERS)) {
+		/*
+		 * We can't know when the station is asleep or awake, so we
+		 * must disable the queue hang detection.
+		 */
+		if (fw_has_capa(&mvm->fw->ucode_capa,
+				IWL_UCODE_TLV_CAPA_STA_PM_NOTIF) &&
+		    vif && vif->type == NL80211_IFTYPE_AP)
+			return IWL_WATCHDOG_DISABLED;
 		return iwlmvm_mod_params.tfd_q_hang_detect ?
 			default_timeout : IWL_WATCHDOG_DISABLED;
+	}
 
 	trigger = iwl_fw_dbg_get_trigger(mvm->fw, FW_DBG_TRIGGER_TXQ_TIMERS);
 	txq_timer = (void *)trigger->data;

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/iwlwifi-mvm-fix-packet-injection.patch queue-4.14/iwlwifi-mvm-don-t-use-transmit-queue-hang-detection-when-it-is-not-possible.patch