On Mon, Mar 10, 2025 at 11:57:41AM +0100, Christian Marangi wrote:

quoted

quoted

+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.

quoted

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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