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: Fri, 30 Nov 2018 07:20:27 +0100 Message-ID: <325a028e-ce95-1055-1b59-ed6120eeb229@gmail.com> References: <0499fc01-fce3-26c7-8b42-64788b8bf47b@gmail.com> <20181130133738.813D.4A936039@socionext.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: Andrew Lunn , "David S. Miller" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Kunihiko Hayashi , Florian Fainelli Return-path: In-Reply-To: <20181130133738.813D.4A936039@socionext.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 30.11.2018 05:37, Kunihiko Hayashi wrote: > Hi Heiner Florian, > > Thank you for your comments. > > On Thu, 29 Nov 2018 16:37:48 -0800 wrote: > >> >> >> On 11/29/2018 2:47 PM, Heiner Kallweit wrote: >>> 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. > > Indeed. I didn't consider the case that the PHY was started but a cable was > unplugged before hibernation. > >>> 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. >> >> Agreed, that would make sense. > > I agree, too. > I'll try this in v2 patch that changes the PHY state to PHY_UP and calls > phy_start_machine(), only when the PHY was started before hibernation. > If I understand correctly, it will be like that: > > phydev->link = 0; Even this may go into the if clause. If PHY isn't started then phydev->link should be 0 anyway. > if (phy_is_started(phydev)) { > phydev->state = PHY_UP; > phy_start_machine(phydev); > } > Yes, this is what was meant. Thanks. > Thank you, > > --- > Best Regards, > Kunihiko Hayashi > > >