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From:   Stanislaw Gruszka <sgruszka@redhat.com>
To:     linux-wireless@vger.kernel.org
Cc:     Felix Fietkau <nbd@nbd.name>,
        Lorenzo Bianconi <lorenzo.bianconi@redhat.com>,
        Ryder Lee <ryder.lee@mediatek.com>, Roy Luo <royluo@google.com>
Subject: [RFC] mt76: fix tx hung regression on MT7630E 
Date:   Fri, 26 Jul 2019 14:10:56 +0200
Message-Id: <1564143056-14610-1-git-send-email-sgruszka@redhat.com>
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

Since 41634aa8d6db ("mt76: only schedule txqs from the tx tasklet")
I can observe firmware hangs on MT7630E on station mode: tx stop
functioning after minor activity (rx keep working) and on module
unload device fail to stop with messages:

[ 5446.141413] mt76x0e 0000:06:00.0: TX DMA did not stop
[ 5449.176764] mt76x0e 0000:06:00.0: TX DMA did not stop

Loading module again results in failure to associate with AP.
Only machine power off / power on cycle can make device work again.

I have no idea why the commit caused F/W hangs. Most likely some proper
fix is needed of changing registers programming (or assuring proper order
of actions), but so far I can not came up with any better fix than
a partial revert of 41634aa8d6db.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
---
 drivers/net/wireless/mediatek/mt76/tx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/tx.c b/drivers/net/wireless/mediatek/mt76/tx.c
index 5397827668b9..fefe0ee52584 100644
--- a/drivers/net/wireless/mediatek/mt76/tx.c
+++ b/drivers/net/wireless/mediatek/mt76/tx.c
@@ -598,7 +598,7 @@ void mt76_wake_tx_queue(struct ieee80211_hw *hw, struct ieee80211_txq *txq)
 	if (!test_bit(MT76_STATE_RUNNING, &dev->state))
 		return;
 
-	tasklet_schedule(&dev->tx_tasklet);
+	mt76_txq_schedule(dev, txq->ac);
 }
 EXPORT_SYMBOL_GPL(mt76_wake_tx_queue);
 
-- 
1.9.3