From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiner Kallweit Subject: Re: [RFC PATCH net] net: phy: fix the issue that netif always links up after resuming Date: Thu, 29 Nov 2018 23:47:38 +0100 Message-ID: <0499fc01-fce3-26c7-8b42-64788b8bf47b@gmail.com> References: <1543479131-14097-1-git-send-email-hayashi.kunihiko@socionext.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Kunihiko Hayashi , Andrew Lunn , Florian Fainelli , "David S. Miller" Return-path: In-Reply-To: <1543479131-14097-1-git-send-email-hayashi.kunihiko@socionext.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 29.11.2018 09:12, Kunihiko Hayashi wrote: > Even though the link is down before entering hibernation, > there is an issue that the network interface always links up after resuming > from hibernation. > > The phydev->state is PHY_READY before enabling the network interface, so > the link is down. After resuming from hibernation, the phydev->state is > forcibly set to PHY_UP in mdio_bus_phy_restore(), and the link becomes up. > > This patch expects to solve the issue by changing phydev->state to PHY_UP > only when the link is up. > > Signed-off-by: Kunihiko Hayashi > --- > drivers/net/phy/phy_device.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c > index ab33d17..d5bba0f 100644 > --- a/drivers/net/phy/phy_device.c > +++ b/drivers/net/phy/phy_device.c > @@ -309,8 +309,10 @@ static int mdio_bus_phy_restore(struct device *dev) > return ret; > > /* The PHY needs to renegotiate. */ > - phydev->link = 0; > - phydev->state = PHY_UP; > + if (phydev->link) { > + phydev->link = 0; > + phydev->state = PHY_UP; > + } > Thanks for reporting. I agree that it isn't right to unconditionally set PHY_UP, because we don't know whether the PHY was started before hibernation. However I don't think using phydev->link as criteria is right. Example would be: PHY was started before hibernation, but w/o link. In this case we want to set PHY_UP to start an aneg, because a cable may have been plugged in whilst system was sleeping. So I think, similar to phy_stop_machine, we should use state >= UP and state != HALTED as criteria, and also phy_start_machine() would need to be called only if this criteria is met. It may make sense to add a helper for checking whether PHY is in a started state (>=UP && !=HALTED), because we need this in more than one place. > phy_start_machine(phydev); > >