From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12708C0650F for ; Mon, 5 Aug 2019 10:01:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E789E20856 for ; Mon, 5 Aug 2019 10:01:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728113AbfHEKBQ (ORCPT ); Mon, 5 Aug 2019 06:01:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51762 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727328AbfHEKBP (ORCPT ); Mon, 5 Aug 2019 06:01:15 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8D4FBCA36F; Mon, 5 Aug 2019 10:01:15 +0000 (UTC) Received: from localhost (ovpn-204-27.brq.redhat.com [10.40.204.27]) by smtp.corp.redhat.com (Postfix) with ESMTP id E61431001B02; Mon, 5 Aug 2019 10:01:12 +0000 (UTC) Date: Mon, 5 Aug 2019 12:01:11 +0200 From: Stanislaw Gruszka To: Lorenzo Bianconi Cc: linux-wireless@vger.kernel.org, Felix Fietkau , Ryder Lee , Roy Luo Subject: Re: [RFC] mt76: fix tx hung regression on MT7630E Message-ID: <20190805100110.GA17889@redhat.com> References: <1564143056-14610-1-git-send-email-sgruszka@redhat.com> <20190729125351.GA3086@redhat.com> <20190729140241.GC4030@localhost.localdomain> <20190730135450.GA2361@redhat.com> <20190730145531.GA3813@localhost.localdomain> <20190731081957.GA4096@redhat.com> <20190731085147.GB4096@redhat.com> <20190731090927.GA3665@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190731090927.GA3665@localhost.localdomain> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Mon, 05 Aug 2019 10:01:15 +0000 (UTC) Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org 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. Stanislaw