From aecdc63d87891c75e60906973c7b7c9cd58403d6 Mon Sep 17 00:00:00 2001 From: Emmanuel Grumbach Date: Wed, 29 Jul 2015 23:06:41 +0300 Subject: [PATCH] iwlwifi: pcie: fix stuck queue detection for sleeping clients The stuck queue detection mechanism allows to detect queues that are stuck. For sleeping clients, a queue may rightfully be stuck: if a poor client implementation stays asleep for more than 10s, then we don't want to trigger recovery flows because of that client. In order to cope with this, I added a mechanism that monitors the state of the client: when a client goes to sleep, the timer of his queues is frozen. When he wakes up, the timer is reset to the right value so that if a client was awake for more than 10s and the queues are stuck, only then, the recovery flow will kick in. This is valid only on non-shared queues: A-MPDU queues. There was a bug in case we Tx to a sleeping client that has an empty A-MPDU queue: the timer was armed to now + 10s. This is bad, but pretty harmless. The problem is that when the client wakes up, the timer is modified to be now + remainder. But remainder is 0 since the queue was empty when that client went to sleep... Fix this by checking the state of the client before playing with the timer when we add a packet to an empty queue. Signed-off-by: Emmanuel Grumbach --- drivers/net/wireless/iwlwifi/pcie/tx.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/iwlwifi/pcie/tx.c b/drivers/net/wireless/iwlwifi/pcie/tx.c index 2b86c2135de3..607acb53c847 100644 --- a/drivers/net/wireless/iwlwifi/pcie/tx.c +++ b/drivers/net/wireless/iwlwifi/pcie/tx.c @@ -1875,8 +1875,19 @@ int iwl_trans_pcie_tx(struct iwl_trans *trans, struct sk_buff *skb, /* start timer if queue currently empty */ if (q->read_ptr == q->write_ptr) { - if (txq->wd_timeout) - mod_timer(&txq->stuck_timer, jiffies + txq->wd_timeout); + if (txq->wd_timeout) { + /* + * If the TXQ is active, then set the timer, if not, + * set the timer in remainder so that the timer will + * be armed with the right value when the station will + * wake up. + */ + if (!txq->frozen) + mod_timer(&txq->stuck_timer, + jiffies + txq->wd_timeout); + else + txq->frozen_expiry_remainder = txq->wd_timeout; + } IWL_DEBUG_RPM(trans, "Q: %d first tx - take ref\n", q->id); iwl_trans_pcie_ref(trans); } -- 2.34.1