Re: [PATCH net] net: phy: Avoid WARN_ON for PHY_NOLINK during resuming

[Kunihiko Hayashi]

On 2022/10/21 20:12, Heiner Kallweit wrote:
> On 21.10.2022 11:35, Kunihiko Hayashi wrote:
> > Hi Heiner,
> >
> > Thank you for your comment.
> >
> > On 2022/10/21 17:38, Heiner Kallweit wrote:
> > > On 21.10.2022 09:41, Kunihiko Hayashi wrote:
> > > > When resuming from sleep, if there is a time lag from link-down to
> > > > link-up
> > > > due to auto-negotiation, the phy status has been still PHY_NOLINK, so
> > > > WARN_ON dump occurs in mdio_bus_phy_resume(). For example, UniPhier AVE
> > > > ethernet takes about a few seconds to link up after resuming.
> > > That autoneg takes some time is normal. If this would actually the root
> > > cause then basically every driver should be affected. But it's not.
> >
> > Although the auto-neg should happen normally, I'm not sure about other
> > platforms.
> >
> > > > To avoid this issue, should remove PHY_NOLINK the WARN_ON conditions.
> > > >
> > > > Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>
> > > > ---
> > > >    drivers/net/phy/phy_device.c | 8 ++++----
> > > >    1 file changed, 4 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> > > > index 57849ac0384e..c647d027bb5d 100644
> > > > --- a/drivers/net/phy/phy_device.c
> > > > +++ b/drivers/net/phy/phy_device.c
> > > > @@ -318,12 +318,12 @@ static __maybe_unused int
> > > > mdio_bus_phy_resume(struct
> > > > device *dev)
> > > >        phydev->suspended_by_mdio_bus = 0;
> > > >
> > > >        /* If we managed to get here with the PHY state machine in a state
> > > > -     * neither PHY_HALTED, PHY_READY nor PHY_UP, this is an indication
> > > > -     * that something went wrong and we should most likely be using
> > > > -     * MAC managed PM, but we are not.
> > > > +     * neither PHY_HALTED, PHY_READY, PHY_UP nor PHY_NOLINK, this is an
> > > > +     * indication that something went wrong and we should most likely
> > > > +     * be using MAC managed PM, but we are not.
> > > >         */
> > >
> > > Did you read the comment you're changing? ave_resume() calls
> > > phy_resume(),
> > > so you should follow the advice in the comment.
> >
> > I understand something is wrong with "PHY_NOLINK" here, and need to
> > investigate
> > the root cause of the phy state issue.
> Best look at how phydev->mac_managed_pm is used in phylib and by MAC
> drivers.

Thank you for the clue!
I'll try the flag and check the behavior of MAC/PHY.

Thank you,

---
Best Regards
Kunihiko Hayashi