SNDRV_PCM_IOCTL_START 592 include/uapi/sound/asound.h #define SNDRV_PCM_IOCTL_START _IO('A', 0x42) SNDRV_PCM_IOCTL_START 592 tools/include/uapi/sound/asound.h #define SNDRV_PCM_IOCTL_START _IO('A', 0x42)