quoted

However, I've just tripped over some information in the 88E1111
manual which states that in SGMII mode, if bypass mode is used, then
the PHY will apparently renegotiate on the copper side advertising
1000baseT HD and FD only, no pause. So I checked what my link partner
is seeing, and it was seeing the original advertisement.

So I then triggered a renegotiate from the partner, and it now shows
only 1000baseT/Half 1000baseT/Full being advertised by the 88E1111.
Reading the advertisement register, it still contains 0x0d41, which
shows pause modes, 100FD, 10FD - so the advertisement register doesn't
reflect what was actually adfertised in this case.

Also, presumably, based on this observation, it will only renegotiate
if the copper side hadn't resolved to gigabit. If correct, what this
means is that when operating in SGMII mode, the the PHY becomes
gigabit-only if bypass mode gets used.

Given this behaviour, the fact that it switches to gigabit only when
the SGMII side enters bypass mode, I think we should _positively_ be
disabling inband bypass in SGMII mode. This change in advertisement
is not what phylib would expect, and I suspect could lead to surprises
e.g. if phylib was told to advertise non-gigabit speeds only.

Sorry, i've not been reading this thread.

This behaviour is not very nice. So i agree, it should be avoided if
possible.

quoted

Thanks for testing. So that means m88e1111_config_init_sgmii() will not
enable in-band if it was previously disabled. So we need to check the
fiber ANENABLE bit and unconditionally return PHY_AN_INBAND_OFF if it is
clear before evaluating anything else.

Also, given this behaviour of bypass mode, it seems it would only make
sense if the PHY were operating in 1000base-X mode, which we don't do
with SFPs, so maybe it makes no sense to support the ON_TIMEOUT as an
option right now - and as I say above, maybe we should be focing the
AN bypass allow bit to be clear in SGMII mode.

I think maybe Andrew needs to be involved in that last bit though.

As you say, 1000Base-X does not make much sense for a copper
SFP. SGMII does odd things, so just not supporting ON_TIMEOUT seems
reasonable.

	Andrew