  We consider the equilibrium partition function of an ideal gas of Dirac
fermions minimally coupled to torsion in $2+1$ dimensions. We show that the
energy-momentum tensor reproduces the Hall viscosity and other parity violating
terms of first order in the torsion. We also consider the modifications of the
constitutive relations, and classify the corresponding susceptibilities. An
entropy current consistent with zero production of entropy in equilibrium is
constructed.
