Date:   Sun, 28 Nov 2021 17:33:14 +0100
From:   Andrew Lunn <andrew@lunn.ch>
To:     Tianhao Chai <cth451@gmail.com>
Cc:     Igor Russkikh <irusskikh@marvell.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Hector Martin <marcan@marcan.st>,
        Sven Peter <sven@svenpeter.dev>,
        Alyssa Rosenzweig <alyssa@rosenzweig.io>
Subject: Re: [PATCH] ethernet: aquantia: Try MAC address from device tree
Message-ID: <YaOvShya4kP4SRk7@lunn.ch>
References: <20211128023733.GA466664@cth-desktop-dorm.mad.wi.cth451.me>
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On Sat, Nov 27, 2021 at 08:37:33PM -0600, Tianhao Chai wrote:
> Apple M1 Mac minis (2020) with 10GE NICs do not have MAC address in the
> card, but instead need to obtain MAC addresses from the device tree. In
> this case the hardware will report an invalid MAC.
> 
> Currently atlantic driver does not query the DT for MAC address and will
> randomly assign a MAC if the NIC doesn't have a permanent MAC burnt in.
> This patch causes the driver to perfer a valid MAC address from OF (if
> present) over HW self-reported MAC and only fall back to a random MAC
> address when neither of them is valid.

This is a change in behaviour, and could cause regressions. It would
be better to keep with the current flow. Call
aq_fw_ops->get_mac_permanent() first. If that does not give a valid
MAC address, then try DT, and lastly use a random MAC address.

    Andrew