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Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral

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Hi Andrew,

On Thu, May 18, 2017 at 9:34 PM, Andrew Lunn <andrew@lunn.ch> wrote:
>> > This most certainly works fine in the simple case where you have one PHY
>> > hanging off the MDIO bus, now what happens if you have several?
>> >
>> > Presumably, the first PHY that returns EPROBE_DEFER will make the entire
>> > bus registration return EPROB_DEFER as well, and so on, and so forth,
>> > but I am not sure if we will be properly unwinding the successful
>> > registration of PHYs that either don't have an interrupt, or did not
>> > return EPROBE_DEFER.
>> >
>> > It should be possible to mimic this behavior by using the fixed PHY, and
>> > possibly the dsa_loop.c driver which would create 4 ports, expecting 4
>> > fixed PHYs to be present.
>>
>> mdiobus_unregister(), called from of_mdiobus_register() on failure,
>> should do the unwinding, right?
>>
>> And when the driver is reprobed, all PHYs are reprobed, until they all
>> succeed.
>
> That is the theory. I looked at that while reviewing the patch. But
> this has probably not been tested in anger. It would be good to test
> this properly, with not just the first PHY returning -EPROBE_DEFER, to
> really test the unwind.

Unfortunately I don't have a board with multiple PHYs, so I cannot test
that case.

Does unbinding/rebinding a network driver with multiple PHYs currently
work? Or module unload/reload?

That should exercise a similar code path.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

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[PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral Geert Uytterhoeven <geert+renesas@glider.be> - 2017-05-18 15:00 +0200
  Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral David Miller <davem@davemloft.net> - 2017-05-18 17:30 +0200
  Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral Andrew Lunn <andrew@lunn.ch> - 2017-05-18 18:10 +0200
    Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral Geert Uytterhoeven <geert@linux-m68k.org> - 2017-05-18 18:20 +0200
      Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral Andrew Lunn <andrew@lunn.ch> - 2017-05-18 18:40 +0200
        Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral Geert Uytterhoeven <geert@linux-m68k.org> - 2017-05-18 19:40 +0200
  Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral Florian Fainelli <f.fainelli@gmail.com> - 2017-05-18 20:30 +0200
    Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral Geert Uytterhoeven <geert@linux-m68k.org> - 2017-05-18 20:50 +0200
      Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral Andrew Lunn <andrew@lunn.ch> - 2017-05-18 21:40 +0200
        Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral Geert Uytterhoeven <geert@linux-m68k.org> - 2017-05-18 22:40 +0200
          Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral Florian Fainelli <f.fainelli@gmail.com> - 2017-05-19 00:30 +0200
            Re: [PATCH] of_mdio: Fix broken PHY IRQ in case of probe deferral Geert Uytterhoeven <geert@linux-m68k.org> - 2017-05-23 11:40 +0200

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