I recently modified devn_get_params to return PageSpotColors since I needed
that to get color_info.max_components set correctly (see bug 693557), but
noticed that this function just returns dummy functions. In general, the
goal is to be able put deviceparams and then read back the same ones with
get.

For reference, the code (with my modification for PageSpotColors) is:
{
    int code;
    bool seprs = false;
    gs_param_string_array scna;
    gs_param_string_array sona;

    set_param_array(scna, NULL, 0);
    set_param_array(sona, NULL, 0);

    if ( (code = sample_device_crd_get_params(pdev, plist, "CRDDefault")) < 0 ||
         (code =
            param_write_name_array(plist, "SeparationColorNames", &scna)) < 0 ||
         (code = param_write_name_array(plist, "SeparationOrder", &sona)) < 0 ||
         (code = param_write_bool(plist, "Separations", &seprs)) < 0 ||
         (code = param_write_int(plist, "PageSpotColors", &(pdevn_params->page_spot_colors))) < 0)
        return code;

    return 0;
}

Unless I am missing something, this always returns empty arrays for the
SeparationColorNames and SeparationOrder and always returns 'false' for
Separations.

Doesn't seem right to me.