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From: Ivan Bornyakov <i.bornyakov@metrotek.ru>
To: Andrew Lunn <andrew@lunn.ch>
Cc: system@metrotek.ru, hkallweit1@gmail.com, linux@armlinux.org.uk,
	davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 1/2] net: phy: marvell-88x2222: check that link is operational
Date: Tue, 13 Apr 2021 10:19:30 +0300	[thread overview]
Message-ID: <20210413071930.52vfjkewkufl7hrb@dhcp-179.ddg> (raw)
In-Reply-To: <YHTacMwlsR8Wl5q/@lunn.ch>

On Tue, Apr 13, 2021 at 01:40:32AM +0200, Andrew Lunn wrote:
> On Mon, Apr 12, 2021 at 03:16:59PM +0300, Ivan Bornyakov wrote:
> > Some SFP modules uses RX_LOS for link indication. In such cases link
> > will be always up, even without cable connected. RX_LOS changes will
> > trigger link_up()/link_down() upstream operations. Thus, check that SFP
> > link is operational before actual read link status.
> 
> Sorry, but this is not making much sense to me.
> 
> LOS just indicates some sort of light is coming into the device. You
> have no idea what sort of light. The transceiver might be able to
> decode that light and get sync, it might not. It is important that
> mv2222_read_status() returns the line side status. Has it been able to
> achieve sync? That should be independent of LOS. Or are you saying the
> transceiver is reporting sync, despite no light coming in?
> 
> 	Andrew

Yes, with some SFP modules transceiver is reporting sync despite no
light coming in. So, the idea is to check that link is somewhat
operational before determing line-side status. 


  reply	other threads:[~2021-04-13  7:19 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-12 12:16 [PATCH net-next 0/2] net: phy: marvell-88x2222: a couple of improvements Ivan Bornyakov
2021-04-12 12:16 ` [PATCH net-next 1/2] net: phy: marvell-88x2222: check that link is operational Ivan Bornyakov
2021-04-12 23:32   ` Marek Behún
2021-04-13  7:13     ` Ivan Bornyakov
2021-04-13 13:07       ` Andrew Lunn
2021-04-12 23:40   ` Andrew Lunn
2021-04-13  7:19     ` Ivan Bornyakov [this message]
2021-04-13  9:23       ` Russell King - ARM Linux admin
2021-04-13 10:06         ` Ivan Bornyakov
2021-04-13 13:12         ` Andrew Lunn
2021-04-13 13:16           ` Russell King - ARM Linux admin
2021-04-12 12:17 ` [PATCH net-next 2/2] net: phy: marvell-88x2222: swap 1G/10G modes on autoneg Ivan Bornyakov

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