netdev - Re: [RFC PATCH net-next] net: phy: force phy suspend when calling phy

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Message-ID: <b12df315-3fcf-dbe3-9e25-f2ecafe752d5@huawei.com>
Date:   Wed, 28 Aug 2019 09:03:44 +0800
From:   "shenjian (K)" <shenjian15@...wei.com>
To:     Heiner Kallweit <hkallweit1@...il.com>, <andrew@...n.ch>,
        <f.fainelli@...il.com>, <davem@...emloft.net>
CC:     <netdev@...r.kernel.org>, <forest.zhouchang@...wei.com>,
        <linuxarm@...wei.com>
Subject: Re: [RFC PATCH net-next] net: phy: force phy suspend when calling
 phy_stop



在 2019/8/28 3:41, Heiner Kallweit 写道:
> On 27.08.2019 10:29, shenjian (K) wrote:
>>
>>
>> 在 2019/8/27 13:51, Heiner Kallweit 写道:
>>> On 27.08.2019 04:47, Jian Shen wrote:
>>>> Some ethernet drivers may call phy_start() and phy_stop() from
>>>> ndo_open and ndo_close() respectively.
>>>>
>>>> When network cable is unconnected, and operate like below:
>>>> step 1: ifconfig ethX up -> ndo_open -> phy_start ->start
>>>> autoneg, and phy is no link.
>>>> step 2: ifconfig ethX down -> ndo_close -> phy_stop -> just stop
>>>> phy state machine.
>>>> step 3: plugin the network cable, and autoneg complete, then
>>>> LED for link status will be on.
>>>> step 4: ethtool ethX --> see the result of "Link detected" is no.
>>>>
>>> Step 3 and 4 seem to be unrelated to the actual issue.
>>> With which MAC + PHY driver did you observe this?
>>>
>> Thanks Heiner,
>>
>> I tested this on HNS3 driver, with two phy, Marvell 88E1512 and RTL8211.
>>
>> Step 3 and Step 4 is just to describe that the LED of link shows link up,
>> but the port information shows no link.
>>
> ethtool refers to the link at MAC level. Therefore default implementation
> ethtool_op_get_link just returns the result of netif_carrier_ok().
> Also using PHY link status if interface is down doesn't really make sense:
> - phylib state machine isn't running, therefore PHY status doesn't get updated
> - often MAC drivers shut down parts of the MAC on ndo_close, this typically
>   makes the internal MDIO bus unaccessible
> So just remove steps 3 and 4. The patch itself is fine with me.
> 
OK, I will fix the commit log.
Thanks, Heiner.
>>
>>>> This patch forces phy suspend even phydev->link is off.
>>>>
>>>> Signed-off-by: Jian Shen <shenjian15@...wei.com>
>>>> ---
>>>>  drivers/net/phy/phy.c | 2 +-
>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
>>>> index f3adea9..0acd5b4 100644
>>>> --- a/drivers/net/phy/phy.c
>>>> +++ b/drivers/net/phy/phy.c
>>>> @@ -911,8 +911,8 @@ void phy_state_machine(struct work_struct *work)
>>>>  		if (phydev->link) {
>>>>  			phydev->link = 0;
>>>>  			phy_link_down(phydev, true);
>>>> -			do_suspend = true;
>>>>  		}
>>>> +		do_suspend = true;
>>>>  		break;
>>>>  	}
>>>>  
>>>>
>>> Heiner
>>>
>>>
>>
>>
> 
> 
> .
>