On Mon, Mar 10, 2025 at 11:57:41AM +0100, Christian Marangi wrote:
> > > +static int an8855_pcs_config(struct phylink_pcs *pcs, unsigned int neg_mode,
> > > + phy_interface_t interface,
> > > + const unsigned long *advertising,
> > > + bool permit_pause_to_mac)
> > > +{
> > > + struct an8855_priv *priv = container_of(pcs, struct an8855_priv, pcs);
> > > + u32 val;
> > > + int ret;
> > > +
> > > + /* !!! WELCOME TO HELL !!! */
> > > +
> > [... hell ...]
>
> Will drop :( It was an easter egg for the 300 lines to configure PCS.
That wasn't a request to drop the comment, just that I didn't want to
include all that in my reply.
> > I guess, however, that as you're only using SGMII with in-band, it
> > probably doesn't make much difference, but having similar behaviour
> > in the various drivers helps with ongoing maintenance.
>
> Do we have some driver that implement the logic of skipping the bulk of
> configuration if the mode doesn't change?
For many, it doesn't matter, but for e.g. xpcs, there may be a reset
of the XPCS when the mode changes, and there's workarounds for the
TXGBE - both of those only happen when the interface mode actually
changes.
Re-reading my .pcs_config() documentation, I really ought to mention
that .pcs_config() will be called for both interface mode changes and
for advertisement changes, and should not disrupt the link when
nothing has changed.
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