On Wed, Sep 30, 2020 at 01:07:19PM -0700, Florian Fainelli wrote:
>
>
> On 9/30/2020 12:09 PM, Andrew Lunn wrote:
> > On Wed, Sep 30, 2020 at 05:47:43PM +0800, Jisheng Zhang wrote:
> > > Hi,
> > >
> > > A GE phy supports pad isolation which can save power in WOL mode. But
> > > once the
> > > isolation is enabled, the MAC can't send/receive pkts to/from the phy
> > > because
> > > the phy is "isolated". To make the PHY work normally, I need to move the
> > > enabling isolation to suspend hook, so far so good. But the isolation
> > > isn't
> > > enabled in system shutdown case, to support this, I want to add shutdown
> > > hook
> > > to net phy_driver, then also enable the isolation in the shutdown hook. Is
> > > there any elegant solution?
> >
> > > Or we can break the assumption: ethernet can still send/receive pkts after
> > > enabling WoL, no?
> >
> > That is not an easy assumption to break. The MAC might be doing WOL,
> > so it needs to be able to receive packets.
> >
> > What you might be able to assume is, if this PHY device has had WOL
> > enabled, it can assume the MAC does not need to send/receive after
> > suspend. The problem is, phy_suspend() will not call into the driver
> > is WOL is enabled, so you have no idea when you can isolate the MAC
> > from the PHY.
> >
> > So adding a shutdown in mdio_driver_register() seems reasonable. But
> > you need to watch out for ordering. Is the MDIO bus driver still
> > running?
>
> If your Ethernet MAC controller implements a shutdown callback and that
> callback takes care of unregistering the network device which should also
> ensure that phy_disconnect() gets called, then your PHY's suspend function
> will be called.
Hi Florian
I could be missing something here, but:
phy_suspend does not call into the PHY driver if WOL is enabled. So
Jisheng needs a way to tell the PHY it should isolate itself from the
MAC, and suspend is not that.
Andrew
