From: Florian Fainelli <f.fainelli@gmail•com>
To: Zefir Kurtisi <zefir.kurtisi@neratec•com>, netdev@vger•kernel.org
Cc: andrew@lunn•ch
Subject: Re: [PATCH v2] phy state machine: failsafe leave invalid RUNNING state
Date: Sun, 8 Jan 2017 17:24:54 -0800 [thread overview]
Message-ID: <5d0f7208-eec2-3b36-d946-e412ec051947@gmail.com> (raw)
In-Reply-To: <1483701288-14019-1-git-send-email-zefir.kurtisi@neratec.com>
On 01/06/2017 03:14 AM, Zefir Kurtisi wrote:
> While in RUNNING state, phy_state_machine() checks for link changes by
> comparing phydev->link before and after calling phy_read_status().
> This works as long as it is guaranteed that phydev->link is never
> changed outside the phy_state_machine().
>
> If in some setups this happens, it causes the state machine to miss
> a link loss and remain RUNNING despite phydev->link being 0.
>
> This has been observed running a dsa setup with a process continuously
> polling the link states over ethtool each second (SNMPD RFC-1213
> agent). Disconnecting the link on a phy followed by a ETHTOOL_GSET
> causes dsa_slave_get_settings() / dsa_slave_get_link_ksettings() to
> call phy_read_status() and with that modify the link status - and
> with that bricking the phy state machine.
>
> This patch adds a fail-safe check while in RUNNING, which causes to
> move to CHANGELINK when the link is gone and we are still RUNNING.
>
> Signed-off-by: Zefir Kurtisi <zefir.kurtisi@neratec•com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail•com>
--
Florian
next prev parent reply other threads:[~2017-01-09 1:25 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-04 15:04 [PATCH] phy state machine: failsafe leave invalid RUNNING state Zefir Kurtisi
2017-01-04 15:13 ` Florian Fainelli
2017-01-04 15:27 ` Zefir Kurtisi
2017-01-04 15:30 ` Florian Fainelli
2017-01-04 16:10 ` Zefir Kurtisi
2017-01-04 16:16 ` Andrew Lunn
2017-01-04 16:24 ` [SIDE DISCUSSION] " Matthias May
2017-01-04 21:44 ` Florian Fainelli
2017-01-05 9:23 ` Zefir Kurtisi
2017-01-05 19:39 ` Florian Fainelli
2017-01-04 20:07 ` kbuild test robot
2017-01-04 20:23 ` kbuild test robot
2017-01-06 11:14 ` [PATCH v2] " Zefir Kurtisi
2017-01-08 23:16 ` David Miller
2017-01-09 1:24 ` Florian Fainelli [this message]
2017-01-09 20:38 ` David Miller
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