Tables of L-shell and L-subshell x-ray production cross sections by protons from 1994 are updated, and the so constructed data base is fitted to formulas for empirical Lα, Lβ, Lγ x-ray production cross sections. Based on these fits, empirical L-subshell ionization cross sections are generated with various sets of atomic parameters with and without alteration for multiple ionizations. The extracted ionization cross sections are compared with the predictions of the ECPSSR theory and it modifications. Based on comparisons with different choice of the atomic parameters and theories, we will recommend an optimal combination of the atomic parameters and ionization theory for a reliable input in PIXE applications software.