netdev - Re: [PATCH iwl-next v2] ice: Disable Cage Max Power override

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Message-ID: <ZO9dhzhK+psufXqS@shredder>
Date: Wed, 30 Aug 2023 18:17:27 +0300
From: Ido Schimmel <idosch@...sch.org>
To: "Drewek, Wojciech" <wojciech.drewek@...el.com>
Cc: Jakub Kicinski <kuba@...nel.org>,
	"intel-wired-lan@...ts.osuosl.org" <intel-wired-lan@...ts.osuosl.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"Kitszel, Przemyslaw" <przemyslaw.kitszel@...el.com>,
	"idosch@...dia.com" <idosch@...dia.com>
Subject: Re: [PATCH iwl-next v2] ice: Disable Cage Max Power override

On Tue, Aug 29, 2023 at 09:12:22AM +0000, Drewek, Wojciech wrote:
> In some cases users are trying to use media with power exceeding max allowed value.
> Port split require system reboot so it feels natural to me to restore default settings.

I don't believe it's the kernel's responsibility to undo changes done by
external tools. Given that the tool is able to change this setting, I
assume it can also restore it back to default.

Moreover, it doesn't sound like port split won't work without this
change, so placing this change there only because we assume that a
reboot will follow seems random.

I think the best way forward is to extend ethtool as was already
suggested. It should allow you to avoid the split brain situation where
the hardware is configured by both the kernel and an external tool.