Subject: Re: [PATCH net] net: mvpp2: fix condition for setting up link interrupt

From: Antoine Tenart <[email-masked]>
Date: Fri, 25 Jan 2019 09:37:20 +0100

Hi,

On Thu, Jan 24, 2019 at 04:07:41PM +0000, Russell King - ARM Linux admin wrote:
> On Thu, Jan 24, 2019 at 04:51:37PM +0100, Andrew Lunn wrote:
> > On Thu, Jan 24, 2019 at 02:18:03PM +0100, Thomas Bogendoerfer wrote:
> > > 
> > > Fixes: 4bb043262878 ("net: mvpp2: phylink support")
> > > Signed-off-by: Thomas Bogendoerfer <[email-masked]>
> > > ---
> > >  drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
> > > index 16066c2d5b3a..0fbfe1945a69 100644
> > > --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
> > > +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
> > > @@ -3405,7 +3405,7 @@ static int mvpp2_open(struct net_device *dev)
> > >  		valid = true;
> > >  	}
> > >  
> > > -	if (priv->hw_version == MVPP22 && port->link_irq && !port->phylink) {
> > > +	if (priv->hw_version == MVPP22 && port->link_irq && port->phylink) {
> > >  		err = request_irq(port->link_irq, mvpp2_link_status_isr, 0,
> > >  				  dev->name, port);
> > >  		if (err) {
> 
> This still looks fishy to me.  mvpp2_link_status_isr() has handling in
> it that is safe to be called for non-phylink cases, so presumably the
> right fix is to drop the "&& !port->phylink" completely?

That's right, mvpp2_link_status_isr() is safe to be called with or
without phylink being used. This IRQ is reporting the link status, and
is used when using in-band status or when phylink isn't used.

We do have a similar fix locally, which looks like:

diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index 2bcbf9caaf0d..6bab1824a1e4 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -3406,7 +3406,8 @@ static int mvpp2_open(struct net_device *dev)
                valid = true;
        }

-       if (priv->hw_version == MVPP22 && port->link_irq && !port->phylink) {
+       if (priv->hw_version == MVPP22 && port->link_irq &&
+           (!port->phylink || !port->has_phy)) {
                err = request_irq(port->link_irq, mvpp2_link_status_isr, 0,
                                  dev->name, port);
                if (err) {

We haven't submitted it yet, as we saw several issues when a port has no
PHY and is using the XLG MAC (so, not on the mcbin). We currently are
working on them.

I don't like to ask this, as you submitted the fix first, but I do think
we should hold back a bit while we figure out proper solutions. If you
need in-band status to be working properly, we could share out current
local branch so you can test and validate it do solve your issue.

Thanks!
Antoine

-- 
Antoine Ténart, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com