/*
  * operators for PCM playback
  */
-static struct snd_pcm_ops vx_pcm_playback_ops = {
+static const struct snd_pcm_ops vx_pcm_playback_ops = {
        .open =         vx_pcm_playback_open,
        .close =        vx_pcm_playback_close,
        .ioctl =        snd_pcm_lib_ioctl,
 /*
  * operators for PCM capture
  */
-static struct snd_pcm_ops vx_pcm_capture_ops = {
+static const struct snd_pcm_ops vx_pcm_capture_ops = {
        .open =         vx_pcm_capture_open,
        .close =        vx_pcm_capture_close,
        .ioctl =        snd_pcm_lib_ioctl,