compat_effect
error = compat_effect(ff, effect);
struct ff_effect_compat *compat_effect;
compat_effect = (struct ff_effect_compat *)effect;
if (copy_from_user(compat_effect, buffer,
if (compat_effect->type == FF_PERIODIC &&
compat_effect->u.periodic.waveform == FF_CUSTOM)
compat_ptr(compat_effect->u.periodic.custom_data);