Re: [PATCH net-next] net: fec: add pm runtime force suspend and resume support

[Andrew Lunn]

On Tue, Sep 06, 2022 at 04:39:23PM +0800, wei.fang@xxxxxxx wrote:
> From: Wei Fang <wei.fang@xxxxxxx>
> 
> Force mii bus into runtime pm suspend state during device suspends,
> since phydev state is already PHY_HALTED, and there is no need to
> access mii bus during device suspend state. Then force mii bus into
> runtime pm resume state when device resumes.

Have you tested this with an Ethernet switch hanging off the MDIO bus?
It has a life cycle of its own, and i'm not sure it is guaranteed that
the switch is suspended before the FEC. That is why the MDIO
read/write functions have there own runtime PM calls, they can be used
when the interface itself is down.

     Andrew