  We investigate the out-of-equilibrium stationary states of spin-Hall devices
on the basis of the least dissipation principle. We show that, for a bulk
paramagnet with spin-orbit interaction, in the case of the Hall bar geometry
the principle of minimum dissipated power prevents the generation of transverse
spin and charge currents while in the case of the Corbino disk geometry,
transverse currents can be produced. More generally, we show that electric
charge accumulation prevents the stationary spin to charge current conversion.
