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Date: Fri, 9 Jun 2023 09:36:07 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: Andrew Lunn <andrew@lunn.ch>, mkubecek@suse.cz, danieller@nvidia.com,
 idosch@nvidia.com, netdev@vger.kernel.org, vladyslavt@nvidia.com
Subject: Re: [PATCH ethtool-next] sff-8636: report LOL / LOS / Tx Fault
Message-ID: <20230609093607.72a8e3f2@kernel.org>
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On Fri, 9 Jun 2023 17:18:27 +0100 Russell King (Oracle) wrote:
> My mental stumbling block is that quad interfaces seem to act as either
> four separate network interfaces, or I think the lanes can be combined
> to double or quadruple the data bandwidth. How this looks from the
> firmware description perspective (in either DT or elsewhere) I don't
> know. Can they be dynamically changed too?

Last question I think I can answer at least from the uAPI perspective -
yes, via the devlink port split API. There's also an ethtool API for
configuring how many lanes are used within a single MAC (e.g. 2x25G vs
1x50G).