From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
To: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: linux-wireless@vger.kernel.org, Felix Fietkau <nbd@nbd.name>,
Ryder Lee <ryder.lee@mediatek.com>, Roy Luo <royluo@google.com>
Subject: Re: [RFC] mt76: fix tx hung regression on MT7630E
Date: Wed, 31 Jul 2019 11:09:27 +0200 [thread overview]
Message-ID: <20190731090927.GA3665@localhost.localdomain> (raw)
In-Reply-To: <20190731085147.GB4096@redhat.com>
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> 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())
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()
Regards,
Lorenzo
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next prev parent reply other threads:[~2019-07-31 9:09 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-26 12:10 [RFC] mt76: fix tx hung regression on MT7630E Stanislaw Gruszka
2019-07-29 12:53 ` Stanislaw Gruszka
2019-07-29 14:02 ` Lorenzo Bianconi
2019-07-30 13:54 ` Stanislaw Gruszka
2019-07-30 14:55 ` Lorenzo Bianconi
2019-07-31 8:19 ` Stanislaw Gruszka
2019-07-31 8:51 ` Stanislaw Gruszka
2019-07-31 9:09 ` Lorenzo Bianconi [this message]
2019-08-05 10:01 ` Stanislaw Gruszka
2019-08-05 11:27 ` Lorenzo Bianconi
2019-08-05 12:39 ` Stanislaw Gruszka
2019-08-12 11:50 ` Stanislaw Gruszka
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