Looking for re(4) help

[mouse%credil.org@localhost]

I'm looking for a little help from someone who knows Realtek Ethernet
chips - specifically, the one with vendor ID 0x10ec and device ID
0x8168, which the machine vendor says is an 8111F.  NetBSD's re(4)
driver works just fine on it; I'm trying to write bare-metal code to
drive the chip.  Packet reception works fine, but packet transmission
does nothing at all as far as I can tell.  I assume I've just missed
some piece of setup somewhere, but I'm having trouble seeing what.

So far I've drawn a complete blank looking for hardware documentation;
I've had to work based on open-source drivers, principally NetBSD's.
I've got an inquiry in to Realtek, but past experiences with vendors
make me not too optimistic about getting help from that quarter.

Any pointers?

/~\ The ASCII				  Mouse
\ / Ribbon Campaign		     mouse%credil.org@localhost
 X  Against HTML		mouse%rodents-montreal.org@localhost
/ \ Email!	     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B