From: Lorenz Brun <lorenz@brun•one>
To: Andrew Lunn <andrew@lunn•ch>
Cc: netdev@vger•kernel.org, Russell King <rmk+kernel@armlinux•org.uk>
Subject: Re: Quirks for exotic SFP module
Date: Sat, 06 May 2023 03:15:07 +0200 [thread overview]
Message-ID: <75Q7UR.PII4PI72J55K3@brun.one> (raw)
In-Reply-To: <8adbd20c-6de0-49ab-aabe-faf845d9a5d9@lunn.ch>
Am Sa, 6. Mai 2023 um 03:05:10 +02:00:00 schrieb Andrew Lunn
<andrew@lunn•ch>:
>> I tested and I got a bunch of addresses showing up on i2c master
>> connected
>> to the module. 1b, 30, 31, 34, 35, 36, 50 and 53. But I'm still not
>> sure why
>> we'd want to talk MDIO with this module. AFAIK MDIO is an Ethernet
>> thing,
>> the module is talking G.fast to the outside which is a completely
>> different
>> protocol from a completely different family of protocols. It has
>> its own
>> management protocol which runs over Ethernet.
>
> One reason you might want to talk to the PHY is to correct is
> configuration. 1000Base-X includes inband signalling. There are some
> Copper SFP which have the inband signalling disabled. And that can
> make the host unhappy, it fails to link up. It varies from host to
> host. Some work, some don't.
Oh, so you're talking about signalling on the AR8033 <-> Linux Host
part of the link. I actually wasn't aware that 1000Base-X did in-band
signalling, TIL. Since the I2C bus is connected to the modem SoC it
would have to forward any MDIO to the AR8033 transceiver, right? This
would also be a bit weird as the AR8033 is connected "backwards", i.e.
with RGMII facing towards the Modem SoC and 1000Base-X towards the
Linux host.
Regards,
Lorenz
next prev parent reply other threads:[~2023-05-06 1:15 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-05 17:39 Quirks for exotic SFP module Lorenz Brun
2023-05-05 18:53 ` Andrew Lunn
2023-05-05 21:30 ` Lorenz Brun
2023-05-06 0:03 ` Andrew Lunn
2023-05-06 0:26 ` Lorenz Brun
2023-05-06 1:05 ` Andrew Lunn
2023-05-06 1:15 ` Lorenz Brun [this message]
2023-05-06 13:35 ` Andrew Lunn
2023-05-06 13:54 ` Russell King (Oracle)
2023-05-06 14:04 ` Lorenz Brun
2023-05-06 10:02 ` Russell King (Oracle)
2023-05-06 10:01 ` Russell King (Oracle)
2023-05-06 9:57 ` Russell King (Oracle)
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