On Thu, Feb 28, 2019 at 12:19:40AM +0100, Andrew Lunn wrote:

quoted

quoted

From what you've described, it sounds like what you actually have is:

	MAC <---> Serdes PHY <---> PHY

The Serdes PHY receives the SGMII in-band negotiation from the external
PHY, but there is no propagation of the status from the serdes PHY to
the MAC.

Yes, that is a good description. So far, we have not yet got the MAC
to read the speed and duplex from the SERDES to configure itself. In
theory it should be able to, it is all in the same device.

It might be that once the SERDES interrupts saying it has link we need
to program the MAC with the result of the in-band signalling. in-band
then seems a bit pointless. Or we are missing some configuration
somewhere to tell the MAC to use the in-band signalling result from
the SERDES.

in-band doesn't become pointless if we can't read from the PHY at the
other end of the in-band link (for example, a Microtik copper SFP
module with an AR8033 on, which has no connectivity to the host other
than the serdes lane.)

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up