Because the SMSC PHY completes auto-negotiation before the driver is
ready to handle interrupts, the PHY state machine never realizes that we
have a link. Clear the ANENABLE bit on initialization, which lets
genphy_config_aneg do its thing when that code is hit later.
While this patch does fix the problem we see (no link on boot without
re-plugging the cable), it seems like the generic PHY code should be
able to handle auto-negotiation completing before interrupts are
enabled. Submitted as an RFC in the hopes that someone has an idea as to
how that could be done.
This fix is copied from commit 99f81afc139c ("phy: micrel: Disable auto
negotiation on startup").
Signed-off-by: Kyle Roeschley <[email protected]>
---
drivers/net/phy/smsc.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c
index b62c4aa..8de8011 100644
--- a/drivers/net/phy/smsc.c
+++ b/drivers/net/phy/smsc.c
@@ -62,6 +62,16 @@ static int smsc_phy_config_init(struct phy_device *phydev)
return rc;
}
+ if (phy_interrupt_is_valid(phydev)) {
+ rc = phy_read(phydev, MII_BMCR);
+ if (rc < 0)
+ return rc;
+
+ rc = phy_write(phydev, MII_BMCR, rc & ~BMCR_ANENABLE);
+ if (rc < 0)
+ return rc;
+ }
+
return smsc_phy_ack_interrupt(phydev);
}
--
2.9.3
On 10/10/2016 12:41 PM, Kyle Roeschley wrote:
> Because the SMSC PHY completes auto-negotiation before the driver is
> ready to handle interrupts, the PHY state machine never realizes that we
> have a link. Clear the ANENABLE bit on initialization, which lets
> genphy_config_aneg do its thing when that code is hit later.
>
> While this patch does fix the problem we see (no link on boot without
> re-plugging the cable), it seems like the generic PHY code should be
> able to handle auto-negotiation completing before interrupts are
> enabled. Submitted as an RFC in the hopes that someone has an idea as to
> how that could be done.
Hi,
Which smsc chip/driver? Maybe assuring the device interrupts are
enabled before the phy is started is a solution?
The whole problem sounds similar to what was recently happening in the
smsc911x driver, but AFAIK that driver is basically only polling at this
point so connecting the phy before the interrupts are enabled shouldn't
be a problem.
>
> This fix is copied from commit 99f81afc139c ("phy: micrel: Disable auto
> negotiation on startup").
>
> Signed-off-by: Kyle Roeschley <[email protected]>
> ---
> drivers/net/phy/smsc.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c
> index b62c4aa..8de8011 100644
> --- a/drivers/net/phy/smsc.c
> +++ b/drivers/net/phy/smsc.c
> @@ -62,6 +62,16 @@ static int smsc_phy_config_init(struct phy_device *phydev)
> return rc;
> }
>
> + if (phy_interrupt_is_valid(phydev)) {
> + rc = phy_read(phydev, MII_BMCR);
> + if (rc < 0)
> + return rc;
> +
> + rc = phy_write(phydev, MII_BMCR, rc & ~BMCR_ANENABLE);
> + if (rc < 0)
> + return rc;
> + }
> +
> return smsc_phy_ack_interrupt(phydev);
> }
>
>
On 10/10/2016 10:41 AM, Kyle Roeschley wrote:
> Because the SMSC PHY completes auto-negotiation before the driver is
> ready to handle interrupts, the PHY state machine never realizes that we
> have a link. Clear the ANENABLE bit on initialization, which lets
> genphy_config_aneg do its thing when that code is hit later.
>
> While this patch does fix the problem we see (no link on boot without
> re-plugging the cable), it seems like the generic PHY code should be
> able to handle auto-negotiation completing before interrupts are
> enabled. Submitted as an RFC in the hopes that someone has an idea as to
> how that could be done.
>
> This fix is copied from commit 99f81afc139c ("phy: micrel: Disable auto
> negotiation on startup").
Do you mind trying:
https://www.spinics.net/lists/netdev/msg397857.html
and see if you do get link interrupts without your patch applied? Thanks!
--
Florian
On Wed, Oct 12, 2016 at 02:13:06AM -0700, Florian Fainelli wrote:
> On 10/10/2016 10:41 AM, Kyle Roeschley wrote:
> > Because the SMSC PHY completes auto-negotiation before the driver is
> > ready to handle interrupts, the PHY state machine never realizes that we
> > have a link. Clear the ANENABLE bit on initialization, which lets
> > genphy_config_aneg do its thing when that code is hit later.
> >
> > While this patch does fix the problem we see (no link on boot without
> > re-plugging the cable), it seems like the generic PHY code should be
> > able to handle auto-negotiation completing before interrupts are
> > enabled. Submitted as an RFC in the hopes that someone has an idea as to
> > how that could be done.
> >
> > This fix is copied from commit 99f81afc139c ("phy: micrel: Disable auto
> > negotiation on startup").
>
> Do you mind trying:
>
> https://www.spinics.net/lists/netdev/msg397857.html
>
> and see if you do get link interrupts without your patch applied? Thanks!
Yep, that fixes it. I figured there was some state machine issue I was missing.
Thanks very much!
> --
> Florian
--
Kyle Roeschley
Software Engineer
National Instruments
On Tue, Oct 11, 2016 at 09:32:30AM -0500, Jeremy Linton wrote:
> On 10/10/2016 12:41 PM, Kyle Roeschley wrote:
> > Because the SMSC PHY completes auto-negotiation before the driver is
> > ready to handle interrupts, the PHY state machine never realizes that we
> > have a link. Clear the ANENABLE bit on initialization, which lets
> > genphy_config_aneg do its thing when that code is hit later.
> >
> > While this patch does fix the problem we see (no link on boot without
> > re-plugging the cable), it seems like the generic PHY code should be
> > able to handle auto-negotiation completing before interrupts are
> > enabled. Submitted as an RFC in the hopes that someone has an idea as to
> > how that could be done.
>
> Hi,
>
> Which smsc chip/driver? Maybe assuring the device interrupts are enabled
> before the phy is started is a solution?
>
> The whole problem sounds similar to what was recently happening in the
> smsc911x driver, but AFAIK that driver is basically only polling at this
> point so connecting the phy before the interrupts are enabled shouldn't be a
> problem.
>
We're using the SMSC LAN8720A with the Cadence MACB ethernet controller.
Interrupts are enabled before the phy is started, but it looks like the patch
Florian pointed me to (https://www.spinics.net/lists/netdev/msg397857.html)
fixes my interrupt problem.
> >
> > This fix is copied from commit 99f81afc139c ("phy: micrel: Disable auto
> > negotiation on startup").
> >
> > Signed-off-by: Kyle Roeschley <[email protected]>
> > ---
> > drivers/net/phy/smsc.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> > diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c
> > index b62c4aa..8de8011 100644
> > --- a/drivers/net/phy/smsc.c
> > +++ b/drivers/net/phy/smsc.c
> > @@ -62,6 +62,16 @@ static int smsc_phy_config_init(struct phy_device *phydev)
> > return rc;
> > }
> >
> > + if (phy_interrupt_is_valid(phydev)) {
> > + rc = phy_read(phydev, MII_BMCR);
> > + if (rc < 0)
> > + return rc;
> > +
> > + rc = phy_write(phydev, MII_BMCR, rc & ~BMCR_ANENABLE);
> > + if (rc < 0)
> > + return rc;
> > + }
> > +
> > return smsc_phy_ack_interrupt(phydev);
> > }
> >
> >
>
--
Kyle Roeschley
Software Engineer
National Instruments
On Wed, Oct 12, 2016 at 10:05:33AM -0500, Kyle Roeschley wrote:
> On Wed, Oct 12, 2016 at 02:13:06AM -0700, Florian Fainelli wrote:
> > On 10/10/2016 10:41 AM, Kyle Roeschley wrote:
> > > Because the SMSC PHY completes auto-negotiation before the driver is
> > > ready to handle interrupts, the PHY state machine never realizes that we
> > > have a link. Clear the ANENABLE bit on initialization, which lets
> > > genphy_config_aneg do its thing when that code is hit later.
> > >
> > > While this patch does fix the problem we see (no link on boot without
> > > re-plugging the cable), it seems like the generic PHY code should be
> > > able to handle auto-negotiation completing before interrupts are
> > > enabled. Submitted as an RFC in the hopes that someone has an idea as to
> > > how that could be done.
> > >
> > > This fix is copied from commit 99f81afc139c ("phy: micrel: Disable auto
> > > negotiation on startup").
> >
> > Do you mind trying:
> >
> > https://www.spinics.net/lists/netdev/msg397857.html
> >
> > and see if you do get link interrupts without your patch applied? Thanks!
>
> Yep, that fixes it. I figured there was some state machine issue I was missing.
> Thanks very much!
Humm, O.K, time to pull that patch out of the series and make it
standalone.
Andrew