netdev - Re: [PATCH] phy: added a PHY_BUSY state into phy_state

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Message-ID: <CAFHy5LCtuG4aB0iFgD7VaW_-vOOQSWbGuMGj2qyNs2+WGZ+J3A@mail.gmail.com>
Date:   Mon, 8 Jul 2019 23:31:58 -0400
From:   kwangdo yi <kwangdo.yi@...il.com>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     Florian Fainelli <f.fainelli@...il.com>, netdev@...r.kernel.org,
        Heiner Kallweit <hkallweit1@...il.com>
Subject: Re: [PATCH] phy: added a PHY_BUSY state into phy_state_machine

On Mon, Jul 8, 2019 at 11:22 PM Andrew Lunn <andrew@...n.ch> wrote:
>
> On Mon, Jul 08, 2019 at 11:16:02PM -0400, kwangdo yi wrote:
> > I simply fixed this issue by increasing the polling time from 20 msec to
> > 60 msec in Xilinx EMAC driver. But the state machine would be in a
> > better shape if it is capable of handling sub system driver's fake failure.
> > PHY device driver could advertising the min/max timeouts for its subsystem,
> > but still some vendor's EMAC driver fails to meet the deadline if this value
> > is not set properly in PHY driver.
>
> Hi Kwangdo
>
> That is not how MDIO works. The PHY has two clock cycles to prepare
> its response to any request. There is no min/max. This was always an
> MDIO bus driver problem, not a PHY problem.
>
>     Andrew

Hi Andrew,

I don't think PHY driver has a problem, nor EMAC driver has, but if PHY driver
is capable of handling EMAC driver's fake failure, the PHY driver would be in
a better fit. That's the intention of this patch.

But, it seems this timeout needs to be handled in each MDIO driver properly.
Thanks.

Regards,