Messages in this thread | | | Date | Wed, 11 Oct 2023 16:25:26 +0200 | From | Oleksij Rempel <> | Subject | Re: [PATCH net-next v1 3/3] net: phy: micrel: Fix forced link mode for KSZ886X switches |
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Hi Alexander,
thank you for review!
On Wed, Oct 11, 2023 at 03:29:49PM +0200, Alexander Stein wrote: > Hi Oleksij, > > Am Mittwoch, 11. Oktober 2023, 14:38:56 CEST schrieb Oleksij Rempel: > > Address a link speed detection issue in KSZ886X PHY driver when in > > forced link mode. Previously, link partners like "ASIX AX88772B" > > with KSZ8873 could fall back to 10Mbit instead of configured 100Mbit. > > > > The issue arises as KSZ886X PHY continues sending Fast Link Pulses (FLPs) > > even with autonegotiation off, misleading link partners in autoneg mode, > > leading to incorrect link speed detection. > > > > Now, when autonegotiation is disabled, the driver sets the link state > > forcefully using KSZ886X_CTRL_FORCE_LINK bit. This action, beyond just > > disabling autonegotiation, makes the PHY state more reliably detected by > > link partners using parallel detection, thus fixing the link speed > > misconfiguration. > > > > With autonegotiation enabled, link state is not forced, allowing proper > > autonegotiation process participation. > > > > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> > > --- > > drivers/net/phy/micrel.c | 32 +++++++++++++++++++++++++++++--- > > 1 file changed, 29 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c > > index 927d3d54658e..12f093aed4ff 100644 > > --- a/drivers/net/phy/micrel.c > > +++ b/drivers/net/phy/micrel.c > > @@ -1729,9 +1729,35 @@ static int ksz886x_config_aneg(struct phy_device > > *phydev) { > > int ret; > > > > - ret = genphy_config_aneg(phydev); > > - if (ret) > > - return ret; > > + if (phydev->autoneg != AUTONEG_ENABLE) { > > + ret = genphy_setup_forced(phydev); > > + if (ret) > > + return ret; > > + > > + /* When autonegotation is disabled, we need to manually > force > > + * the link state. If we don't do this, the PHY will keep > > + * sending Fast Link Pulses (FLPs) which are part of the > > + * autonegotiation process. This is not desired when > > + * autonegotiation is off. > > + */ > > + ret = phy_set_bits(phydev, MII_KSZPHY_CTRL, > > + KSZ886X_CTRL_FORCE_LINK); > > + if (ret) > > + return ret; > > + } else { > > + /* Make sure, the link state is not forced. > > + * Otherwise, the PHY we create a link by skipping the > > PHY will create? > > > + * autonegotiation process. > > + */ > > + ret = phy_clear_bits(phydev, MII_KSZPHY_CTRL, > > + KSZ886X_CTRL_FORCE_LINK); > > + if (ret) > > + return ret; > > Isn't this call to phy_clear_bits() a fix for autonegotiation mode? This > should be a separate patch then.
First time this bit is set by this patch, I assume this problem would not exist without fixed link fix.
Regards, Oleksij -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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