From: "Lothar Waßmann" <LW@KARO-electronics.de>
To: Andrew Lunn <andrew@lunn.ch>
Cc: "David S. Miller" <davem@davemloft.net>,
"Fabio Estevam" <fabio.estevam@freescale.com>,
"Kevin Hao" <haokexin@gmail.com>,
"Lucas Stach" <l.stach@pengutronix.de>,
"Nimrod Andy" <B38611@freescale.com>,
"Philippe Reynes" <tremyfr@gmail.com>,
"Russell King" <rmk+kernel@arm.linux.org.uk>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
"Stefan Agner" <stefan@agner.ch>
Subject: Re: [PATCH] net: fec: fix enet_out clock handling
Date: Mon, 30 Nov 2015 06:37:02 +0100 [thread overview]
Message-ID: <20151130063702.22d24834@ipc1.ka-ro> (raw)
In-Reply-To: <20151130020731.GB32662@lunn.ch>
Hi,
> On Fri, Nov 27, 2015 at 02:39:10PM +0100, Lothar Waßmann wrote:
> > When ENET_OUT is being used as reference clock for an external PHY,
> > the clock must not be disabled while the PHY is active. Otherwise the
> > PHY may lose its internal state and require a reset to become
> > functional again.
> >
> > A symptom for this bug is a network interface that constantly toggles
> > between UP and DOWN state:
> > fec 800f0000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
> > fec 800f0000.ethernet eth0: Link is Down
> > fec 800f0000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
> > fec 800f0000.ethernet eth0: Link is Down
>
> Hi Lothar
>
> When does this up/down happen? During normal operation when the link
> is administrative up?
>
If booting with NFSROOT the rootfs cannot be mounted, because when the
interface is brought up the PHY starts toggling the link state.
> When did this start happening? Did it happen before
> 8fff755e9f8d net: fec: Ensure clocks are enabled while using mdio bus
>
No. The behaviour started exactly with this commit.
Lothar Waßmann
prev parent reply other threads:[~2015-11-30 5:37 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-27 13:39 [PATCH] net: fec: fix enet_out clock handling Lothar Waßmann
2015-11-27 15:16 ` Michael Heimpold
2015-11-28 13:13 ` Duan Andy
2015-11-28 16:43 ` Andrew Lunn
2015-11-30 1:46 ` Duan Andy
2015-11-30 1:58 ` Andrew Lunn
2015-11-30 6:56 ` Lothar Waßmann
2015-11-30 7:31 ` Duan Andy
2015-11-30 2:07 ` Andrew Lunn
2015-11-30 5:37 ` Lothar Waßmann [this message]
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