Re: [PATCH 1/1] Workaround for Suspend/Resume issue of AX88772B under ChromeOS

From: Grant Grundler
Date: Thu Nov 21 2013 - 21:26:44 EST


On Thu, Nov 21, 2013 at 5:58 PM, Florian Fainelli <f.fainelli@xxxxxxxxx> wrote:
...
>> Freddy sent me a patch that saves/restores MII_ADVERTISE and MII_BMCR
>> registers. Testing that now and he'll post if that all works out.

Bad News: Freddy's patch didn't work and needs to be rework it.

> That should be enough to ensure the PHY is put back into a consistent
> state. So long as you are suspending/resuming from a configuration
> where autoneg was enabled, I would not expect anything bad to happen.

Well, I think davem NACK'd that approach (the original patch in this
thread did that).

> If the link was forced, that is a different story.
>
> One way to make sure this work properly without driver-specific code
> is to include that functionality into the PHY library. As far as I can
> see it the asix drivers do not use it but implement the old-style
> mii_bus interface so that would be a first step.

AFAICT, many USBNET drivers support mii_bus interface. Can you point
at a good example of a USBNET driver that is supporting PHY lib?

I also didn't see anything in usbnet_resume() code path that calls
into a phy lib. So it seems that some infrastructure still needs to
happen if that's considered a feasible.

thanks,
grant

> --
> Florian
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