USX2Y_HWDEP_PCM_PAGES
usx2y->hwdep_pcm_shm = alloc_pages_exact(USX2Y_HWDEP_PCM_PAGES,
memset(usx2y->hwdep_pcm_shm, 0, USX2Y_HWDEP_PCM_PAGES);
if (size > USX2Y_HWDEP_PCM_PAGES) {
size, (unsigned long)USX2Y_HWDEP_PCM_PAGES);
free_pages_exact(usx2y->hwdep_pcm_shm, USX2Y_HWDEP_PCM_PAGES);