linux-kernel - Re: [PATCH net-next v1 4/4] net: phy: mxl-gpy: disable interrupts on GPY215 by default

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Message-ID: <Y4uzYVSRiE9feD01@lunn.ch>
Date:   Sat, 3 Dec 2022 21:36:49 +0100
From:   Andrew Lunn <andrew@...n.ch>
To:     Michael Walle <michael@...le.cc>
Cc:     Xu Liang <lxu@...linear.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S . Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH net-next v1 4/4] net: phy: mxl-gpy: disable interrupts on
 GPY215 by default

> > > @@ -290,6 +291,10 @@ static int gpy_probe(struct phy_device *phydev)
> > >  	phydev->priv = priv;
> > >  	mutex_init(&priv->mbox_lock);
> > > 
> > > +	if (gpy_has_broken_mdint(phydev) &&
> > > +	    !device_property_present(dev,
> > > "maxlinear,use-broken-interrupts"))
> > > +		phydev->irq = PHY_POLL;
> > > +
> > 
> > I'm not sure of ordering here. It could be phydev->irq is set after
> > probe. The IRQ is requested as part of phy_connect_direct(), which is
> > much later.
> 
> I've did it that way, because phy_probe() also sets phydev->irq = PHY_POLL
> in some cases and the phy driver .probe() is called right after it.

Yes, it is a valid point to do this check, but on its own i don't
think it is sufficient.

> > I think a better place for this test is in gpy_config_intr(), return
> > -EOPNOTSUPP. phy_enable_interrupts() failing should then cause
> > phy_request_interrupt() to use polling.
> 
> Which will then print a warning, which might be misleading.
> Or we disable the warning if -EOPNOTSUPP is returned?

Disabling the warning is the right thing to do.

	  Andrew