properly. This causes the autonegotiation to e.g. never establish a
100baseTX full-duplex link. The solution to this problem is to manually
write the capabilities from the BMSR to the ANAR every time a media
change occurs, even when already in autonegotiation mode.
The NetBSD way of doing this is to set their MIIF_FORCEANEG flag in the
NIC driver. This causes mii_phy_setmedia() to call mii_phy_auto() (which
will set the ANAR according to the BMSR) even when the PHY alread is in
autonegotiation mode. However, while doing the same on FreeBSD (which
involves porting the MIIF_FORCEANEG flag and converting nsphy.c to use
mii_phy_setmedia()) fixes autonegotiation, using mii_phy_setmedia()
causes this driver to no longer work properly in the other modes.
Another drawback of that approach is that this will also force writing
the ANAR on other PHYs whose drivers use mii_phy_setmedia() and which
are used with a NIC whose driver sets MIIF_FORCEANEG (e.g. hme(4) is
known to be used together with 3 different PHYs while only the DP83840A
require this workaround).
So instead of moving to MIIF_FORCEANEG, just call mii_phy_auto() in
nsphy_service() unconditionally when hanging off of a hme(4) and serving
a media change
This is part 1/2 of fixing autonegotiation on hme(4) using DP83840A PHYs.
f0e531572d