 rawmidi handle for output  */ static int snd_virmidi_output_open(struct snd_rawmidi_substream *substream) {  struct snd_virmidi_dev *rdev = substream->rmidi->private_data;  struct snd_rawmidi_runtime *runtime = substream->runtime;  struct snd_virmidi *vmidi;   vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);  if (vmidi == NULL)   return -ENOMEM;  vmidi->substream = substream;  if (snd_midi_event_new(