From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pavel Machek <pavel@ucw.cz>
Subject: Re: stmmac tx timeout
Date: Tue, 13 Jun 2017 10:38:52 +0200
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Cc: Alexandre Torgue <alexandre.torgue@st.com>,
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        Joao Pinto <Joao.Pinto@synopsys.com>,
        Lars Persson <larper@axis.com>, netdev <netdev@vger.kernel.org>
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Hi!

> > @@ -2043,7 +2063,11 @@ static netdev_tx_t stmmac_xmit(struct sk_buff
> > *skb, stru\
> > ct net_device *dev)
> >         } else
> > 	                priv->tx_count_frames =3D 0;
> >=20
> > +       dma_rmb();
> > +       dma_wmb();
> >         /* To avoid raise condition */
> > +       BUG_ON(first->des01.etx.own); /* This BUG_ON seems to be enough.
> > +                                          Replacing it with barriers i=
s _not_enough. */
> >         priv->hw->desc->set_tx_owner(first);
> >  	wmb();
> >=20
> > No, the BUG_ON() does not trigger. Yes, it still fixes the driver for
> > me. You may want to verify it has same effect for you.
>=20
> Hello Pavel,
>=20
> I am sincerely grateful for you help.
>=20
> I forward ported your patch to 4.9,
> however, I could still get tx timeouts.
>=20
> Thankfully I finally found the root cause of
> my tx timeouts, see the patch I've submitted
> here:
>=20
> http://marc.info/?l=3Dlinux-kernel&m=3D149673393525236

Thanks a lot for the information. And unfortunately yes, there's
probably more work to do in the stmmac driver; for example it would be
good if _tx_timeout were actually able to recover the card. I probably
have patch for that somewhere, too...

Best regards,
									Pavel
--=20
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo=
g.html

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