  Avila and Viana exhibit an explicit sufficient condition for the Lyapunov
exponents of a linear cocycle over a Markov map to have multiplicity 1. Here,
in terms of geometric perturbations, we prove that this sufficient criterion is
generic in the space of all fiber bunched linear cocycles over Markov maps: the
set of exceptional cocycles has infinite codimention, i.e. it is locally
contained in finite unions of closed submanifolds with arbitrarily high
codimension.
