On Sun, Jan 24, 2021 at 12:36 AM Danielle Ratson [off-list ref] wrote:

quoted

Why isn't this also handled using a capability bit as is done for
lanes? Is link_mode read-only? Should it / will it always be? If not,
can drivers also derive the other fields if asked to set link_mode?

The link_mode param is only for deriving all the speed, lanes and duplex params in ethtool instead of deriving in driver and then > passing each individual, as Michal asked.

I understand the benefit of deriving the dependent fields in core code
rather than in each driver, I just don't think this is necessarily
mutually exclusive with being able to force a particular link mode at
the driver API, making link_mode R/W (and even extend this interface
to user space). For a driver that works internally in terms of the
link_mode it's returning, this would be more natural.

quoted

That would be easy enough. Why don't we simply allow user space to set
link mode directly too (in addition to being able to constrain lanes
for autoneg or forced speeds)?

It is already possible to do using 'advertise' parameter.

That's not the same thing. If it were, you wouldn't need the lanes
parameter in the first place.

Regards,
Edwin Peer