From 67e1daa0bb30eda6ec5add27c3abf4536030f5a6 Mon Sep 17 00:00:00 2001 From: Daniel Mack Date: Mon, 31 May 2010 13:35:43 +0200 Subject: [PATCH] ALSA: usb-audio: clean up find_audio_control_unit() Use a struct to parse the audio units, and return usable descriptors for all types. There's no need to limit the result set, except for some kind of sanity check. Signed-off-by: Daniel Mack Signed-off-by: Takashi Iwai --- sound/usb/mixer.c | 18 ++++++++++-------- 1 file 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 */ -- GitLab