netdev - Re: [PATCH net] net: phylink: fix link state on phy-connect

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Message-ID: <20171129195911.GG8356@n2100.armlinux.org.uk>
Date:   Wed, 29 Nov 2017 19:59:12 +0000
From:   Russell King - ARM Linux <linux@...linux.org.uk>
To:     Yan Markman <ymarkman@...vell.com>
Cc:     Antoine Tenart <antoine.tenart@...e-electrons.com>,
        "andrew@...n.ch" <andrew@...n.ch>,
        "f.fainelli@...il.com" <f.fainelli@...il.com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "gregory.clement@...e-electrons.com" 
        <gregory.clement@...e-electrons.com>,
        "thomas.petazzoni@...e-electrons.com" 
        <thomas.petazzoni@...e-electrons.com>,
        "miquel.raynal@...e-electrons.com" <miquel.raynal@...e-electrons.com>,
        Nadav Haklai <nadavh@...vell.com>,
        "mw@...ihalf.com" <mw@...ihalf.com>,
        Stefan Chulski <stefanc@...vell.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH net] net: phylink: fix link state on phy-connect

On Wed, Nov 29, 2017 at 07:33:44PM +0000, Yan Markman wrote:
> Hi Russel
> 
> On my board I have [Marvell 88E1510] phy working with STATUS-POLLING
> I see some inconsistencies  -- first ifconfig-up is different from furthers, no "link is down" reports.
> Please refer the behavior example below.
> My patch is a "simple solution"  -- always reset/clear Link-state-parameters before going UP.
> Possibly, more correct (but much more complicated) solution would be in the   phy state machine   and   phylink resolve modification.
> I just found that 
>     On ifconfig-down, the phy-state-machine and phylink-resolve
>     are stopped before executing before passing over full graceful down/reset state.
>     The further ifconfig-up starts with old state parameters.
> Special cases not-tested but logic 2 test-cases are:
>    remote side changes speed whilst link is Down or Disconnected. But local ifconfig-up starts with old speed.

Hi,

I think this is covered in my "phy" branch - but could probably do with
further testing, specifically this patch (which I've attached):

"phylink: ensure we take the link down when phylink_stop() is called"

This takes the link down on the MAC side synchronously when phylink_stop()
is called.  However, I think your case might also benefit from this
patch - please test the patch referred to without this change, and let
me know if you need this change to solve your problem:

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 8f43f8779317..c90ad50204b0 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -798,6 +798,7 @@ void phylink_disconnect_phy(struct phylink *pl)
 		mutex_lock(&pl->state_mutex);
 		pl->netdev->phydev = NULL;
 		pl->phydev = NULL;
+		pl->phy_state.link = false;
 		mutex_unlock(&pl->state_mutex);
 		mutex_unlock(&phy->lock);
 		flush_work(&pl->resolve);

Thanks.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up
According to speedtest.net: 8.21Mbps down 510kbps up

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