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SubjectRe: [PATCH net] net: mvpp2: fix condition for setting up link interrupt
On Fri, Jan 25, 2019 at 09:37:20AM +0100, Antoine Tenart wrote:
> 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 <tbogendoerfer@suse.de>
> > > > ---
> > > > 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.

Hi Antoine,

Today, I received an email from Willy Tarreau about this issue which
persists to this day with mainline kernels.

Willy reminded me that I've been carrying a fix for this, but because
of your concerns as stated above, I haven't bothered submitting it
through fear of causing regressions (which you seem to know about):

http://git.armlinux.org.uk/cgit/linux-arm.git/commit/?h=mvpp2&id=67ef3bff255b26cc0d6def8ca99c4e8ae9937727

Just like Thomas' case, the current code is broken for phylink when
in-band negotiation is being used - such as with the 1G/2.5G SFP
slot on the Macchiatobin.

It seems that resolving the issue has stalled. Can I merge my patch,
or could you state exactly what the problems are with it so that
someone else can look into the issues please?

Thanks.

--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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