On 11/29/2018 2:47 PM, Heiner Kallweit wrote:

On 29.11.2018 09:12, Kunihiko Hayashi wrote:

quoted

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.

Agreed, that would make sense.
-- 
Florian