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Commit 67e1daa0 authored by Daniel Mack's avatar Daniel Mack Committed by Takashi Iwai
Browse files

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: default avatarDaniel Mack <daniel@caiaq.de>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 2e0281d1

sound/usb/mixer.c

+10 −8
Original line number Diff line number Diff line
@@ -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,

	while ((hdr = snd_usb_find_desc(state->buffer, state->buflen, hdr,

					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;

		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

 */