From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: [RFC PATCH net] net: phy: fix the issue that netif always links up after resuming Date: Thu, 29 Nov 2018 16:37:48 -0800 Message-ID: References: <1543479131-14097-1-git-send-email-hayashi.kunihiko@socionext.com> <0499fc01-fce3-26c7-8b42-64788b8bf47b@gmail.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: Heiner Kallweit , Kunihiko Hayashi , Andrew Lunn , "David S. Miller" Return-path: In-Reply-To: <0499fc01-fce3-26c7-8b42-64788b8bf47b@gmail.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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. > > 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. -- Florian