Re: [PATCH] net: phy: Don't disable irqs on shutdown if WoL is enabled

Florian Fainelli
2023-08-09T17:04:40Z

On 8/9/2023 9:21 AM, Andrew Lunn wrote:
>> Thinking about this, I wonder whether we could solve your issue by
>> disabling interrupts when the PHY is probed, rather than disabling
>> them on shutdown - something like this? (not build tested)
>>
>> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
>> index 3e9909b30938..4d1a37487923 100644
>> --- a/drivers/net/phy/phy_device.c
>> +++ b/drivers/net/phy/phy_device.c
>> @@ -3216,6 +3216,8 @@ static int phy_probe(struct device *dev)
>> goto out;
>> }
>>
>> + phy_disable_interrupts(phydev);
>> +
>> /* Start out supporting everything. Eventually,
>> * a controller will attach, and may modify one
>> * or both of these values
>
> At some point, the interrupt is going to be enabled again. And then
> the WoL interrupt will fire. I think some PHY drivers actually need to
> see that WoL interrupt. e.g. the marvell driver has this comment:
>
> static int m88e1318_set_wol(struct phy_device *phydev,
> struct ethtool_wolinfo *wol)
> {
> ....
> /* If WOL event happened once, the LED[2] interrupt pin
> * will not be cleared unless we reading the interrupt status
> * register. If interrupts are in use, the normal interrupt
> * handling will clear the WOL event. Clear the WOL event
> * before enabling it if !phy_interrupt_is_valid()
> */
>
> So it seems like just probing the marvell PHY is not enough to clear
> the WoL interrupt.
>
> Can we be sure that the other PHY has reached a state it can handle
> and clear an interrupt when we come to enable the interrupt? I think
> not, especially in cases like NFS root, where the interface will be
> put into use as soon as it exists, maybe before the other interface
> has probed.

Does it really make sense to have the PHY be interrupt driven for this
specific board configuration if this causes so much hassle?
--
Florian