Re: [PATCH net-next v2] net: dsa: microchip: Add SGMII port support to KSZ9477 switch

[Vladimir Oltean]

On Fri, Jan 17, 2025 at 12:56:14AM +0000, Tristram.Ha@xxxxxxxxxxxxx wrote:
> The KSZ9477 SGMII module does use DesignWare IP, but its implementation
> is probably too old as some registers do not match.  When using XPCS
> driver link detection works but the SGMII port does not pass traffic for
> some SFPs.  It is probably doable to update the XPCS driver to work in
> KSZ9477, but there is no way to submit that patch as that may affect
> other hardware implementation.
> 
> One thing that is strange is that driver enables interrupt for 1000BaseX
> mode but not SGMII mode, but in KSZ9477 SGMII mode can trigger link up
> and link down interrupt but 1000BaseX can only trigger link up interrupt.

Sometimes, the "collaborative" aspect of open source projects does work
out, and you might get help, feedback and/or regression testing for
hardware you don't have. Sure, it doesn't always work out, but I suggest
you give it a try and not put the cart before the horses.