When running an Illumos based distro (in this case the latest smartos-live), one can occasionally see 'WARNING: rtls0: Failure resetting PHY.' on the console. This is due to the MII_CONTROL register having the PHY reset bit set, while the emulated device never clears it. The MII layer phy reset code waits for this bit to clear or time out. When it times out, the warning is displayed. Since it likely makes no sense to do anything for a requested PHY reset, a simple fix is to mask the PHY reset bit out when updating the MII_CONTROL (aka BASIC_MODE_CONTROL) register.
A trivial patch at http://pastie.org/2546257 fixes this (tested with latest smartos-live image).
Proposed fix LGTM, and I can reproduce the issue here.
Merged in now. See 22237de.