From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kunihiko Hayashi Subject: Re: [RFC PATCH net] net: phy: fix the issue that netif always links up after resuming Date: Fri, 30 Nov 2018 13:37:39 +0900 Message-ID: <20181130133738.813D.4A936039@socionext.com> References: <0499fc01-fce3-26c7-8b42-64788b8bf47b@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Cc: Andrew Lunn , "David S. Miller" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Heiner Kallweit , Florian Fainelli Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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; if (phy_is_started(phydev)) { phydev->state = PHY_UP; phy_start_machine(phydev); } Thank you, --- Best Regards, Kunihiko Hayashi