When is Raoult's Law valid for solid-liquid solution?
It is valid for both volatile and nonvolatile solutes, as it refers to the partial vapour pressure, not total vapour pressure.
Saying that, note that  it applies only on mixtures with  ideal behaviour, as there are many more or less significant  positive and negative deviations from the law. These deviations relate to preference of intermolecular bonding to the same, or to the other molecules.
Typical examples are ethanol water mixture forming an azeotrop of the minimal boiling point,  or hydrochloric acid forming an azeotrop with the maximal boiling point.