usbmix_dB_map
const struct usbmix_dB_map *dB;
static const struct usbmix_dB_map bose_companion5_dB = {-5006, -6};
static const struct usbmix_dB_map bose_soundlink_dB = {-8283, -0, true};
static const struct usbmix_dB_map sennheiser_pc8_dB = {-9500, 0};
static const struct usbmix_dB_map ms_usb_link_dB = { -3225, 0, true };
static const struct usbmix_dB_map mp3plus_dB_1 = {.min = -4781, .max = 0};
static const struct usbmix_dB_map mp3plus_dB_2 = {.min = -1781, .max = 618};