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Date:   Mon, 23 Oct 2023 16:28:04 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     "Jia, Fang" <fang.jia@windriver.com>
Cc:     Heiner Kallweit <hkallweit1@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: phy: fixed link 1000 or 100 set with autoneg off
Message-ID: <dfc37ead-2abe-4053-b0a6-911c9c387451@lunn.ch>
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> Thanks very much for your reply.
> 
> Actually, due to some reason, the phydev's default aneg state is off.
> And we just found if use ethtool to set, it had the same result.

I find it surprising it defaults to aneg off. Are you sure something
has not turned it off before you look at it?

The emulator does not support writing to any registers. However,
fixed_mdio_write() does not return an error, it just does nothing.  It
needs testing, but maybe try making it return -EOPNOTSUPP. That should
prevent auto-neg being turned off, but it might also break everything
if it tries to do some other write during probe or link up. It could
be it needs a more select response, allowing writes to some bits, like
the reset bit, and start auto-neg, but not others like disable
auto-neg.

	Andrew