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From: Antoine Tenart <antoine.tenart@bootlin.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Antoine Tenart <antoine.tenart@bootlin.com>,
	davem@davemloft.net, linux@armlinux.org.uk,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	thomas.petazzoni@bootlin.com, maxime.chevallier@bootlin.com,
	gregory.clement@bootlin.com, miquel.raynal@bootlin.com,
	nadavh@marvell.com, stefanc@marvell.com, ymarkman@marvell.com,
	mw@semihalf.com
Subject: Re: [PATCH net-next 1/2] net: phy: sfp: make the i2c-bus property really optional
Date: Thu, 17 May 2018 15:13:53 +0200	[thread overview]
Message-ID: <20180517131353.GN32746@kwain> (raw)
In-Reply-To: <20180517130406.GH8547@lunn.ch>

On Thu, May 17, 2018 at 03:04:06PM +0200, Andrew Lunn wrote:
> 
> I was thinking about how it reads the bit rate from the EEPROM. From
> that it determines what mode the MAC could use, 1000-Base-X,
> 2500-Base-X, etc. Can you still configure this correctly via ethtool,
> if you don't have the bitrate information?

I see. That's a very good question. When testing this, I used SFP cages
which were not wired *at all*. So it worked because the SFP module
injection never was seen by the kernel, which was then not calling
phylink_sfp_module_insert() and thus not calling sfp_parse_support().

But in cases where the module insertion can be detected, as you pointed
out, I'm not so sure it can work then. I'll wait for other answers, but
we may want to fail when probing such modules as you suggested.

Thanks!
Antoine

-- 
Antoine Ténart, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

  reply	other threads:[~2018-05-17 13:13 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-17  8:29 [PATCH net-next 0/2] net: sfp: small improvements Antoine Tenart
2018-05-17  8:29 ` [PATCH net-next 1/2] net: phy: sfp: make the i2c-bus property really optional Antoine Tenart
2018-05-17 12:41   ` Andrew Lunn
2018-05-17 12:56     ` Antoine Tenart
2018-05-17 13:04       ` Andrew Lunn
2018-05-17 13:13         ` Antoine Tenart [this message]
2018-05-17 15:08         ` Russell King - ARM Linux
2018-05-17 15:01     ` Russell King - ARM Linux
2018-05-17  8:29 ` [PATCH net-next 2/2] net: phy: sfp: warn the user when no tx_disable pin is available Antoine Tenart
2018-05-21 15:51 ` [PATCH net-next 0/2] net: sfp: small improvements David Miller
2018-05-22  9:24   ` Antoine Tenart

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