Re: [PATCH 1/2] net: ethernet: sxgbe: remove private tx queue lock

From: Pavel Machek
Date: Sat Dec 17 2016 - 12:32:11 EST


On Thu 2016-12-15 23:33:22, Lino Sanfilippo wrote:
> On 15.12.2016 22:32, Lino Sanfilippo wrote:
>
> > Ah ok. Then maybe priv->hw->dma->stop_tx() does not do the job correctly (stop the
> > tx path properly) and the HW is still active on the tx path while the tx buffers are
> > freed. OTOH stmmac_release() also stops the phy before the tx (and rx) paths are stopped.
> > Did you try to stop the phy fist in stmmac_tx_err_work(), too?
> >
> > Regards,
> > Lino
> >
>
> And this is the "sledgehammer" approach: Do a complete shutdown and restart
> of the hardware in case of tx error (against net-next and only
>compile tested).

Wow, thanks a lot. I'll try to get the driver back to the non-working
state, and try it.

I believe I have some idea what is wrong there. (Missing memory barriers).

> +static void stmmac_tx_err_work(struct work_struct *work)
> +{
> + struct stmmac_priv *priv = container_of(work, struct stmmac_priv,
> + tx_err_work);
> + /* restart netdev */
> + rtnl_lock();
> + stmmac_release(priv->dev);
> + stmmac_open(priv->dev);
> + rtnl_unlock();
> +}

Won't this up/down the interface, in a way userspace can observe?

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

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