Re: [PATCH 1/3 v3] net: usb: r8152: Check used MAC passthrough address

From: Jakub Kicinski <kuba@kernel.org>
To: "Limonciello, Mario" <mario.limonciello@amd.com>
Cc: Kai-Heng Feng <kai.heng.feng@canonical.com>,
	Andrew Lunn <andrew@lunn.ch>, Oliver Neukum <oneukum@suse.com>,
	Aaron Ma <aaron.ma@canonical.com>,
	henning.schild@siemens.com, linux-usb@vger.kernel.org,
	netdev@vger.kernel.org, davem@davemloft.net,
	hayeswang@realtek.com, tiwai@suse.de
Subject: Re: [PATCH 1/3 v3] net: usb: r8152: Check used MAC passthrough address
Date: Tue, 11 Jan 2022 09:06:48 -0800	[thread overview]
Message-ID: <20220111090648.511e95e8@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net> (raw)
In-Reply-To: <2b779fef-459f-79bb-4005-db4fd3fd057f@amd.com>

On Tue, 11 Jan 2022 10:54:50 -0600 Limonciello, Mario wrote:
> > Also knowing how those OSes handle the new docks which don't have
> > unique device IDs would obviously be great..  
> 
> I'm sorry, can you give me some more context on this?  What unique 
> device IDs?

We used to match the NICs based on their device ID. The USB NICs
present in docks had lenovo as manufacturer and a unique device ID.
Now reportedly the new docks are using generic realtek IDs so we have
no way to differentiate "blessed" dock NICs from random USB dongles,
and inheriting the address to all devices with the generic relatek IDs
breaks setups with multiple dongles, e.g. Henning's setup.

If we know of a fuse that can be read on new docks that'd put us back
in more comfortable position. If we need to execute random heuristics
to find the "right NIC" we'd much rather have udev or NetworkManager 
or some other user space do that according to whatever policy it
chooses.