Re: [PATCH net] net: phy: Fix the issue that netif always links up after resuming

[Heiner Kallweit]

On 18.12.2018 08:57, 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.
> 
> If the link is still down before enabling the network interface,
> and after resuming from hibernation, the phydev->state is forcibly set
> to PHY_UP in mdio_bus_phy_restore(), and the link becomes up.
> 
> In suspend sequence, only if the PHY is attached, mdio_bus_phy_suspend()
> calls phy_stop_machine(), and mdio_bus_phy_resume() calls
> phy_start_machine().
> In resume sequence, it's enough to do the same as mdio_bus_phy_resume()
> because the state has been preserved.
> 
> This patch fixes the issue by calling phy_start_machine() in
> mdio_bus_phy_restore() in the same way as mdio_bus_phy_resume().
> 
The patch itself is fine and also that you tagged it as "net".
What's missing is a "Fixes:" line (before the Suggested-by:).
I think it should be:

Fixes: bc87922ff59d ("phy: Move PHY PM operations into phy_device")

This commit didn't actually introduce the issue, but moved it to today's
place.

> Suggested-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>
> ---
>  drivers/net/phy/phy_device.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
> 
> This patch is based on the RFC patch discussion [1].
> [1] https://www.spinics.net/lists/netdev/msg537326.html
> 
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 7d5d698..3685be4 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -315,11 +315,8 @@ static int mdio_bus_phy_restore(struct device *dev)
>  	if (ret < 0)
>  		return ret;
>  
> -	/* The PHY needs to renegotiate. */
> -	phydev->link = 0;
> -	phydev->state = PHY_UP;
> -
> -	phy_start_machine(phydev);
> +	if (phydev->attached_dev && phydev->adjust_link)
> +		phy_start_machine(phydev);
>  
>  	return 0;
>  }
>