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authorDaniel Mack <daniel@caiaq.de>2010-05-31 13:35:43 +0200
committerTakashi Iwai <tiwai@suse.de>2010-05-31 18:17:49 +0200
commit67e1daa0bb30eda6ec5add27c3abf4536030f5a6 (patch)
tree7309eecb049e51203c9c6500e7f7a054a9503173 /sound/usb
parent2e0281d15c220d0a81c45c73872aa08d2f3ae3ef (diff)
downloadlinux-2.6.34-ux500-67e1daa0bb30eda6ec5add27c3abf4536030f5a6.tar.gz
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 <daniel@caiaq.de> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb')
-rw-r--r--sound/usb/mixer.c18
1 files changed, 10 insertions, 8 deletions
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 8be6bf2552b..cb345360f81 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
*/