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Date: Thu, 6 Jun 2024 20:31:43 +0200
From: Andrew Lunn <andrew@lunn.ch>
To: Jacob Keller <jacob.e.keller@intel.com>
Cc: jackie.jone@alliedtelesis.co.nz, davem@davemloft.net,
	jesse.brandeburg@intel.com, anthony.l.nguyen@intel.com,
	kuba@kernel.org, intel-wired-lan@lists.osuosl.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	chris.packham@alliedtelesis.co.nz
Subject: Re: [PATCH] igb: Add MII write support
Message-ID: <12b1febd-a634-43bb-8edf-79ccb4f9e3aa@lunn.ch>
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 <ad56235d-d267-4477-9c35-210309286ff4@intel.com>
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In-Reply-To: <c12ffb8e-0606-442b-810a-69bf65624bf9@intel.com>

> Yea, its extremely easy to break things if you don't know what you're
> doing here. So its more a question of "are we ok exposing yet another
> way root can brick things?"

Many MAC drivers allow it, and we have not had complaints. It is not
really something i'm a fan of, it in theory allows user space drivers
for PHYs, but it is full of race conditions so in practice unlikely to
work reliably.

If you are worried about it causing additional support issues because
it gets abused, you could make it taint the kernel. That makes it
clear all bets are off if used. For the use case presented here, a
tainted kernel does not matter, it for lab testing, not production.

      Andrew