netdev - Re: [RFC net-next 4/4] net: phy: Correctly process PHY_HALTED in phy_stop

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Date:   Tue, 31 Oct 2017 16:26:01 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Marc Gonzalez <marc_gonzalez@...madesigns.com>,
        "David S. Miller" <davem@...emloft.net>,
        Andrew Lunn <andrew@...n.ch>, opendmb@...il.com,
        Mason <slash.tmp@...e.fr>, David Daney <david.daney@...ium.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>
Subject: Re: [RFC net-next 4/4] net: phy: Correctly process PHY_HALTED in phy_stop_machine()

Hi Florian,

On Mon, Oct 30, 2017 at 5:09 PM, Florian Fainelli <f.fainelli@...il.com> wrote:
> On 10/30/2017 06:56 AM, Geert Uytterhoeven wrote:
>> On Thu, Oct 26, 2017 at 1:21 AM, Florian Fainelli <f.fainelli@...il.com> wrote:
>>> Marc reported that he was not getting the PHY library adjust_link()
>>> callback function to run when calling phy_stop() + phy_disconnect()
>>> which does not indeed happen because we set the state machine to
>>> PHY_HALTED but we don't get to run it to process this state past that
>>> point.
>>>
>>> Fix this with a synchronous call to phy_state_machine() in order to have
>>> the state machine actually act on PHY_HALTED, set the PHY device's link
>>> down, turn the network device's carrier off and finally call the
>>> adjust_link() function.
>>>
>>> At the end of phy_state_machine() though, if we are going to be moving
>>> from PHY_HALTED to PHY_HALTED, do not reschedule the state machine, this
>>> is pointless.
>>>
>>> Reported-by: Marc Gonzalez <marc_gonzalez@...madesigns.com>
>>> Fixes: a390d1f379cf ("phylib: convert state_queue work to delayed_work")
>>> Signed-off-by: Marc Gonzalez <marc_gonzalez@...madesigns.com>
>>> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
>>
>> Thanks for your patch!
>>
>> Unfortunately, after applying this one, the last in your series, both
>> sh73a0/kzm9g and r8a73a4/ape6evm start crashing again in the system
>> suspend/resume path, due to register accesses while the device is already
>> suspended:
>
> OK, seems like there is another path, uncovered by this patch that we
> can be hitting, does the following patch below help?

Unfortunately it doesn't help.

>> Unhandled fault: imprecise external abort (0x1406) at 0x0005b950

Note that this is an imprecise external abort, i.e. it's reporting may
be delayed,
and the backtrace may be inaccurate.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-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