On Wed, Aug 14, 2019 at 11:50:12AM +0200, Lorenzo Bianconi wrote: > > > > 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. > > > > It's unclear why commit 41634aa8d6db causes the problem, but it is > > related to HW encryption. Since issue is a firmware hang, that is super > > hard to debug, just disable HW encryption as fix for the issue. > > > > Fixes: 41634aa8d6db ("mt76: only schedule txqs from the tx tasklet") > > Signed-off-by: Stanislaw Gruszka <sgruszka@xxxxxxxxxx> > > --- > > drivers/net/wireless/mediatek/mt76/mt76x0/pci.c | 15 ++++++++++++++- > > 1 file changed, 14 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/net/wireless/mediatek/mt76/mt76x0/pci.c b/drivers/net/wireless/mediatek/mt76/mt76x0/pci.c > > index 4585e1b756c2..6117e6ca08cb 100644 > > --- a/drivers/net/wireless/mediatek/mt76/mt76x0/pci.c > > +++ b/drivers/net/wireless/mediatek/mt76/mt76x0/pci.c > > @@ -62,6 +62,19 @@ static void mt76x0e_stop(struct ieee80211_hw *hw) > > mt76x0e_stop_hw(dev); > > } > > > > +static int > > +mt76x0e_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd, > > + struct ieee80211_vif *vif, struct ieee80211_sta *sta, > > + struct ieee80211_key_conf *key) > > +{ > > + struct mt76x02_dev *dev = hw->priv; > > + > > + if (is_mt7630(dev)) > > + return -EOPNOTSUPP; > > Hi Stanislaw, > > Can you please try if disabling/enabling the tx tasklet during hw key > configuration fixes the issue? > Doing something like: > > tasklet_disable(tx_tasklet) > mt76x02_set_key() > tasklet_enable(tx_tasklet) It does not help with the problem. > Moreover, have you double checked if there is any performance impact > of not using hw encryption? I didn't observe any, but realized on this machine I have aesni_intel encryption accelerator. After rebuild kernel without CONFIG_CRYPTO_AES_NI_INTEL, 'perf top' showed extra 20% of cpu usage in aes_encrypt() when sending data with HW encryption disabled. > If so, I guess it is better to just redefine mt76_wake_tx_queue for > mt76x0e and run mt76_txq_schedule for 7630e: > > void mt76x0e_wake_tx_queue(struct ieee80211_hw *hw, struct ieee80211_txq *txq) > { > if (is_mt7630(dev)) { > mt76_txq_schedule(dev, txq->ac); > } else { > tasklet_schedule(&dev->tx_tasklet); > } > } Not sure about reduction of lock contention for which the tx_tasklet was introduced here, but looks ok for me as fix. Stanislaw