From: Heiner Kallweit <hkallweit1@gmail.com>
To: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>,
Andrew Lunn <andrew@lunn.ch>,
Florian Fainelli <f.fainelli@gmail.com>,
"David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
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 [thread overview]
Message-ID: <0499fc01-fce3-26c7-8b42-64788b8bf47b@gmail.com> (raw)
In-Reply-To: <1543479131-14097-1-git-send-email-hayashi.kunihiko@socionext.com>
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 <hayashi.kunihiko@socionext.com>
> ---
> 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);
>
>
next prev parent reply other threads:[~2018-11-29 22:47 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-29 8:12 [RFC PATCH net] net: phy: fix the issue that netif always links up after resuming Kunihiko Hayashi
2018-11-29 22:47 ` Heiner Kallweit [this message]
2018-11-30 0:37 ` Florian Fainelli
2018-11-30 4:37 ` Kunihiko Hayashi
2018-11-30 6:20 ` Heiner Kallweit
2018-11-30 6:38 ` Kunihiko Hayashi
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