Re: [PATCH net v1 1/1] net: usb: asix: ax88772: drop phylink use in PM to avoid MDIO runtime PM wakeups

Oleksij Rempel
2025-09-09T07:17:38Z

On Mon, Sep 08, 2025 at 07:00:09PM +0200, Hubert Wiśniewski wrote:
> On Mon Sep 8, 2025 at 1:26 PM CEST, Oleksij Rempel wrote:
> > Drop phylink_{suspend,resume}() from ax88772 PM callbacks.
> >
> > MDIO bus accesses have their own runtime-PM handling and will try to
> > wake the device if it is suspended. Such wake attempts must not happen
> > from PM callbacks while the device PM lock is held. Since phylink
> > {sus|re}sume may trigger MDIO, it must not be called in PM context.
> >
> > No extra phylink PM handling is required for this driver:
> > - .ndo_open/.ndo_stop control the phylink start/stop lifecycle.
> > - ethtool/phylib entry points run in process context, not PM.
> > - phylink MAC ops program the MAC on link changes after resume.
>
> Thanks for the patch! Applied to v6.17-rc5, it fixes the problem for me.
>
> Tested-by: Hubert Wiśniewski <hubert.wisniewski.25632@gmail.com>

Thank you for testing!

> > Fixes: e0bffe3e6894 ("net: asix: ax88772: migrate to phylink")
>
> It does, but v5.15 (including v5.15.191 LTS) is affected as well, from
> 4a2c7217cd5a ("net: usb: asix: ax88772: manage PHY PM from MAC"). I think
> it could also use a patch, but I won't insist.

Ack, I'll try do address it later.

Best Regards,
Oleksij
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