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Date:   Thu, 18 Aug 2022 16:49:49 +0200
From:   Michael Walle <michael@walle.cc>
To:     Vladimir Oltean <vladimir.oltean@nxp.com>
Cc:     devicetree@vger.kernel.org, netdev@vger.kernel.org,
        Shawn Guo <shawnguo@kernel.org>, Li Yang <leoyang.li@nxp.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH devicetree 0/3] NXP LS1028A DT changes for multiple switch
 CPU ports
In-Reply-To: <20220818140519.2767771-1-vladimir.oltean@nxp.com>
References: <20220818140519.2767771-1-vladimir.oltean@nxp.com>
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Am 2022-08-18 16:05, schrieb Vladimir Oltean:
> The Ethernet switch embedded within the NXP LS1028A has 2 Ethernet 
> ports
> towards the host, for local packet termination. In current device 
> trees,
> only the first port is enabled. Enabling the second port allows having 
> a
> higher termination throughput.

Is it used automatically or does the userspace has to configure 
something?

> Care has been taken that this change does not produce regressions when
> using updated device trees with old kernels that do not support 
> multiple
> DSA CPU ports. The only difference for old kernels will be the
> appearance of a new net device (for &enetc_port3) which will not be 
> very
> useful for much of anything.

Mh, I don't understand. Does it now cause regressions or not? I mean
besides that there is a new unused interface?

I was just thinking of that systemready stuff where the u-boot might
supply its (newer) device tree to an older kernel, i.e. an older debian
or similar.

-michael