linux-kernel - Re: [RFC PATCH V2 net] net: phy: Fix "link partner" information disappear issue

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Date:   Tue, 15 Oct 2019 22:02:27 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Yonglong Liu <liuyonglong@...wei.com>, davem@...emloft.net,
        andrew@...n.ch
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        linuxarm@...wei.com, salil.mehta@...wei.com,
        yisen.zhuang@...wei.com, shiju.jose@...wei.com
Subject: Re: [RFC PATCH V2 net] net: phy: Fix "link partner" information
 disappear issue

On 14.10.2019 14:56, Yonglong Liu wrote:
> Some drivers just call phy_ethtool_ksettings_set() to set the
> links, for those phy drivers that use genphy_read_status(), if
> autoneg is on, and the link is up, than execute "ethtool -s
> ethx autoneg on" will cause "link partner" information disappear.
> 
> The call trace is phy_ethtool_ksettings_set()->phy_start_aneg()
> ->linkmode_zero(phydev->lp_advertising)->genphy_read_status(),
> the link didn't change, so genphy_read_status() just return, and
> phydev->lp_advertising is zero now.
> 
> This patch moves the clear operation of lp_advertising from
> phy_start_aneg() to genphy_read_lpa()/genphy_c45_read_lpa(), and
> if autoneg on and autoneg not complete, just clear what the
> generic functions care about.
> 
> Fixes: 88d6272acaaa ("net: phy: avoid unneeded MDIO reads in genphy_read_status")
> Signed-off-by: Yonglong Liu <liuyonglong@...wei.com>
> 
Looks good to me, two small nits below.


> ---
> change log:
> V2: moves the clear operation of lp_advertising from
> phy_start_aneg() to genphy_read_lpa()/genphy_c45_read_lpa(), and
> if autoneg on and autoneg not complete, just clear what the
> generic functions care about. Suggested by Heiner Kallweit.
> ---
> ---
This line seems to be duplicated.

>  drivers/net/phy/phy-c45.c    |  2 ++
>  drivers/net/phy/phy.c        |  3 ---
>  drivers/net/phy/phy_device.c | 12 +++++++++++-
>  3 files changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/phy/phy-c45.c b/drivers/net/phy/phy-c45.c
> index 7935593..a1caeee 100644
> --- a/drivers/net/phy/phy-c45.c
> +++ b/drivers/net/phy/phy-c45.c
> @@ -323,6 +323,8 @@ int genphy_c45_read_pma(struct phy_device *phydev)
>  {
>  	int val;
>  
> +	linkmode_zero(phydev->lp_advertising);
> +
>  	val = phy_read_mmd(phydev, MDIO_MMD_PMAPMD, MDIO_CTRL1);
>  	if (val < 0)
>  		return val;
> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
> index 119e6f4..105d389b 100644
> --- a/drivers/net/phy/phy.c
> +++ b/drivers/net/phy/phy.c
> @@ -572,9 +572,6 @@ int phy_start_aneg(struct phy_device *phydev)
>  	if (AUTONEG_DISABLE == phydev->autoneg)
>  		phy_sanitize_settings(phydev);
>  
> -	/* Invalidate LP advertising flags */
> -	linkmode_zero(phydev->lp_advertising);
> -
>  	err = phy_config_aneg(phydev);
>  	if (err < 0)
>  		goto out_unlock;
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 9d2bbb1..4b43466 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -1787,7 +1787,14 @@ int genphy_read_lpa(struct phy_device *phydev)
>  {
>  	int lpa, lpagb;
>  
> -	if (phydev->autoneg == AUTONEG_ENABLE && phydev->autoneg_complete) {
> +	if (phydev->autoneg == AUTONEG_ENABLE) {
> +		if (!phydev->autoneg_complete) {
> +			mii_stat1000_mod_linkmode_lpa_t(phydev->lp_advertising,
> +							0);
> +			mii_lpa_mod_linkmode_lpa_t(phydev->lp_advertising, 0);
> +			return 0;
> +		}
> +
>  		if (phydev->is_gigabit_capable) {
>  			lpagb = phy_read(phydev, MII_STAT1000);
>  			if (lpagb < 0)
> @@ -1816,6 +1823,9 @@ int genphy_read_lpa(struct phy_device *phydev)
>  
>  		mii_lpa_mod_linkmode_lpa_t(phydev->lp_advertising, lpa);
>  	}
> +	else {

"} else {" should be on one line.

> +		linkmode_zero(phydev->lp_advertising);
> +	}
>  
>  	return 0;
>  }
>