Re: [PATCH net-next v1 3/4] net: phy: do not force EEE support

On Mon, Feb 20, 2023 at 05:13:39PM +0100, Oleksij Rempel wrote:

On Mon, Feb 20, 2023 at 04:48:26PM +0100, Andrew Lunn wrote:

quoted

quoted

Hm.. ethtool do not provide enough information about expected behavior.
Here is my expectation:
- "ethtool --set-eee lan1 eee on" should enable EEE if it is disabled.
- "ethtool --set-eee lan1 advertise 0x10" should change set of
  advertised modes.
- a sequence of "..advertise 0x10", "..eee on", "eee off" should restore
  preconfigured advertise modes. advertising_eee instead of
  supported_eee.

I agree ethtool is not very well documented. However, i would follow
what -s does. You can pass link modes you want to advertise, and you
can turn auto-neg on and off. Does turning auto-neg off and on again
reset the links modes which are advertised? I don't actually know, but
i think the behaviour should be consistent for link modes and EEE
modes.

Hm.. "ethtool -s lan1 autoneg on" will restore supported values. Even
without switching it off.

Remember that -s is for the media capabilities, not EEE. There is
specific handling of the advertising mask in the userspace
ethtool.c::do_sset() but that doesn't exist for EEE, which merely
goes a ETHTOOL_GEEE, modifies the structure according to the arguments
given, and then calls ETHTOOL_SEEE. So:

# ethtool --set-eee lan1 eee on

will merely change eeecmd.eee_enabled to be set if it wasn't already,
but will not change eeecmd.advertised in any way - it'll contain
whatever it did before, which may or may not be zero.

This is in contrast to:

# ethtool -s lan1 autoneg on

which will set the advertisement to be the those that are supported.

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