RE: [PATCH net-next] net: phy: call phy_init_hw() in phy resume path

Biju Das
2026-04-10T17:27:05Z

Hi Russell King/ Andrew,

> -----Original Message-----
> From: Russell King <linux@armlinux.org.uk>
> Sent: 10 April 2026 15:55
> Subject: Re: [PATCH net-next] net: phy: call phy_init_hw() in phy resume path
>
> On Fri, Apr 10, 2026 at 03:51:18PM +0100, Russell King (Oracle) wrote:
> > On Fri, Apr 10, 2026 at 03:29:01PM +0100, Biju wrote:
> > > From: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
> > >
> > > When mac_managed_pm flag is set, mdio_bus_phy_resume() is skipped,
> > > so phy_init_hw(), which performs soft_reset and config_init, is not
> > > called during resume.
> > >
> > > This is inconsistent with the non-mac_managed_pm path, where
> > > mdio_bus_phy_resume() calls phy_init_hw() before phy_resume() on
> > > every resume.
> > >
> > > To align both paths, add a phy_init_hw() call at the top of
> > > __phy_resume(), before invoking the driver's resume callback. This
> > > guarantees the PHY undergoes soft reset and re-initialization
> > > regardless of whether PM is managed by the MAC or the MDIO bus.
> > >
> > > Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
> > > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> > > ---
> > > drivers/net/phy/phy_device.c | 4 ++++
> > > 1 file changed, 4 insertions(+)
> > >
> > > diff --git a/drivers/net/phy/phy_device.c
> > > b/drivers/net/phy/phy_device.c index 0edff47478c2..8255f4208d66
> > > 100644
> > > --- a/drivers/net/phy/phy_device.c
> > > +++ b/drivers/net/phy/phy_device.c
> > > @@ -2008,6 +2008,10 @@ int __phy_resume(struct phy_device *phydev)
> > > if (!phydrv || !phydrv->resume)
> > > return 0;
> > >
> > > + ret = phy_init_hw(phydev);
> > > + if (ret)
> > > + return ret;
> >
> > Do we want to do this even when phydrv->resume is NULL?
>
> I should've also added (sorry, busy packing) - with it always being called even when phydrv->resume is
> NULL, it means that the call sites to phy_resume() in phylib which are preceeded by a call to
> phy_init_hw() should have that call removed, otherwise we're going to be calling phy_init_hw() twice.
>
> As the patch currently stands, that's the case when phydrv->resume is populated, and I think we should
> avoid that.
>
> > Apart from that, looks fine to me - it seems some paths call
> > phy_init_hw() can be called with or without phydev->lock held, and
> > this one will call it with the lock held which seems to be okay.

The new patch will be like this, after moving phy_init_hw() without
phydev->lock held. Please let me know are you ok with this?

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 0edff47478c2..4a2b19d39373 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -396,10 +396,6 @@ static __maybe_unused int mdio_bus_phy_resume(struct device *dev)
WARN_ON(phydev->state != PHY_HALTED && phydev->state != PHY_READY &&
phydev->state != PHY_UP);

- ret = phy_init_hw(phydev);
- if (ret < 0)
- return ret;
-
ret = phy_resume(phydev);
if (ret < 0)
return ret;
@@ -1857,16 +1853,14 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
if (dev)
netif_carrier_off(phydev->attached_dev);

- /* Do initial configuration here, now that
+ /* Do initial configuration inside phy_init_hw(), now that
* we have certain key parameters
* (dev_flags and interface)
*/
- err = phy_init_hw(phydev);
+ err = phy_resume(phydev);
if (err)
goto error;

- phy_resume(phydev);
-
/**
* If the external phy used by current mac interface is managed by
* another mac interface, so we should create a device link between
@@ -2020,6 +2014,10 @@ int phy_resume(struct phy_device *phydev)
{
int ret;

+ ret = phy_init_hw(phydev);
+ if (ret)
+ return ret;
+
mutex_lock(&phydev->lock);
ret = __phy_resume(phydev);
mutex_unlock(&phydev->lock);
--