diff options
| -rw-r--r-- | sound/usb/mixer.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c index 8be6bf2552b0..cb345360f811 100644 --- a/sound/usb/mixer.c +++ b/sound/usb/mixer.c @@ -165,22 +165,24 @@ static int check_mapped_selector_name(struct mixer_build *state, int unitid, /* * find an audio control unit with the given unit id - * this doesn't return any clock related units, so they need to be handled elsewhere */ static void *find_audio_control_unit(struct mixer_build *state, unsigned char unit) { - unsigned char *p; + /* we just parse the header */ + struct uac_feature_unit_descriptor *hdr = NULL; - p = NULL; - while ((p = snd_usb_find_desc(state->buffer, state->buflen, p, - USB_DT_CS_INTERFACE)) != NULL) { - if (p[0] >= 4 && p[2] >= UAC_INPUT_TERMINAL && p[2] <= UAC2_EXTENSION_UNIT_V2 && p[3] == unit) - return p; + while ((hdr = snd_usb_find_desc(state->buffer, state->buflen, hdr, + USB_DT_CS_INTERFACE)) != NULL) { + if (hdr->bLength >= 4 && + hdr->bDescriptorSubtype >= UAC_INPUT_TERMINAL && + hdr->bDescriptorSubtype <= UAC2_SAMPLE_RATE_CONVERTER && + hdr->bUnitID == unit) + return hdr; } + return NULL; } - /* * copy a string with the given id */ |