> On Wed, Jul 31, 2019 at 11:09:27AM +0200, Lorenzo Bianconi wrote: > > > On Wed, Jul 31, 2019 at 10:19:58AM +0200, Stanislaw Gruszka wrote: > > > > On Tue, Jul 30, 2019 at 04:55:31PM +0200, Lorenzo Bianconi wrote: > > > > > > > > diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c b/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c > > > > > > > > index 467b28379870..622251faa415 100644 > > > > > > > > --- a/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c > > > > > > > > +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c > > > > > > > > @@ -170,7 +170,7 @@ static int mt76x02_poll_tx(struct napi_struct *napi, int budget) > > > > > > > > mt76.tx_napi); > > > > > > > > int i; > > > > > > > > > > > > > > > > - mt76x02_mac_poll_tx_status(dev, false); > > > > > > > > + mt76x02_mac_poll_tx_status(dev, true); > > > > > > > > > > > > > > I am not sure if we really need mt76x02_mac_poll_tx_status() here since we run > > > > > > > it in mt76x02_tx_complete_skb() and in mt76x02_tx_tasklet(). Anyway the only > > > > > > > difference doing so is we do not run mt76x02_send_tx_status(). > > > > > > > > > > > > I thought this is the problem, but it was my mistake during testing. > > > > > > I tested the above change together with mt76_txq_schedule(dev, txq->ac) > > > > > > change and get wrong impression it fixes the issue. But above change > > > > > > alone does not help. > > > > > > > > > > > > I tried to add some locking to avoid parallel execution of mt76x02_poll_tx() > > > > > > and mt76x02_tx_tasklet(), but it didn't help either. So far only patch > > > > > > originally posted here make the problem gone. > > > > > > > > > > so, in order to be on the same page, if you comment out mt76x02_mac_poll_tx_status() > > > > > in mt76x02_poll_tx() the issue will still occur. The only to 'fix' it is to run > > > > > mt76_txq_schedule_all() in mt76x02_poll_tx(), right? > > > > > > > > Yes. > > > > > > Err, no, I should read more cerfully. It is partiall revert of > > > 41634aa8d6db ("mt76: only schedule txqs from the tx tasklet") : > > > > > > 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); > > > > reviewing the code I think: > > > > - we should not run mt76u_tx_tasklet() from mt76_wake_tx_queue() since we do > > not have tx_napi for usb and it will unnecessary go through tx queue checks. > > We should probably do in mt76_wake_tx_queue() something like: > > > > if (is_mmio()) > > Adding '&& !is_mt7630()' will solve the problem for MT7630E as well ... > > > tasklet_schedule(&dev->tx_tasklet); > > else > > mt76_txq_schedule(dev, txq->ac); > > > > Another solution would be add a status_tasklet that just goes through the tx > > queues receiving the usb tx completion and it schedules the tx_tasklet > > What do you think? > > > > - I guess it does not fix the 76x0e issue but we should just schedule tx queues in > > mt76x02_tx_tasklet() (like it is done for mt7603 and mt7615) and move status > > processing in mt76x02_poll_tx() > > ... but I think we have bug when do mt76_txq_schedule_all() in > tx_tasklet, because we can schedule on queues that are stoped. > So reverting 41634aa8d6db and then optimize by removing tx_tasklet > for mmio and remove not needed mt76_txq_schedule_all() calls looks > more reasoneble to me. schedule a stopped queue seems not harmful at a first glance since we do not copy pending skbs if we have not enough room in the dma ring. Maybe we can be more conservative doing something like: diff --git a/drivers/net/wireless/mediatek/mt76/dma.c b/drivers/net/wireless/mediatek/mt76/dma.c index d8f61e540bfd..c6482155e5e4 100644 --- a/drivers/net/wireless/mediatek/mt76/dma.c +++ b/drivers/net/wireless/mediatek/mt76/dma.c @@ -346,6 +346,11 @@ mt76_dma_tx_queue_skb(struct mt76_dev *dev, enum mt76_txq_id qid, goto unmap; if (q->queued + (tx_info.nbuf + 1) / 2 >= q->ndesc - 1) { + if (!q->stopped) { + ieee80211_stop_queue(dev->hw, + skb_get_queue_mapping(skb)); + q->stopped = true; + } ret = -ENOMEM; goto unmap; } diff --git a/drivers/net/wireless/mediatek/mt76/tx.c b/drivers/net/wireless/mediatek/mt76/tx.c index 5397827668b9..bd2d34c4f326 100644 --- a/drivers/net/wireless/mediatek/mt76/tx.c +++ b/drivers/net/wireless/mediatek/mt76/tx.c @@ -495,6 +495,9 @@ mt76_txq_schedule_list(struct mt76_dev *dev, enum mt76_txq_id qid) while (1) { bool empty = false; + if (hwq->stopped) + break; + if (sq->swq_queued >= 4) break; Does it fix the issue you are facing? Regards, Lorenzo > > Stanislaw