  We present the results of theoretical study of surface state properties in a
two-dimensional model for triplet $p$-wave superconductors. We derive boundary
conditions for Eilenberger equations at rough interfaces and develop the
approach for self-consistent solution for the spatial dependence of $p_{x}$ and
$p_{x}+i~p_{y}$ -wave pair potentials. In the $p_{x}$ case we demonstrate the
robustness of the zero-energy peak in the density of states (DoS) with respect
to surface roughness, in contrast to the suppression of such a peak in the case
of $d_{xy}$ symmetry. This effect is due to stability of odd-frequency pairing
state at the surface with respect to disorder. In the case of the chiral
$p_{x}+i~p_{y}$ state we demonstrate the appearance of a complex multi-peak
subgap structure in the spectrum with increasing surface roughness.
