ALSA: usb - Don't trust the channel config if the channel count changed (504333df) · Commits · 戴 / test

In case the channel count of the input terminal is not the same as the channel count of the streaming descriptor, the channel config of the input terminal can not be trusted. Instead fall back to a default (guessed) channel map. This was found on a Logitech USB Headset. Signed-off-by:

David Henningsson <david.henningsson@canonical.com> Signed-off-by:

Takashi Iwai <tiwai@suse.de>

sound/usb/stream.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -662,7 +662,6 @@ int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
		* (fp->maxpacksize & 0x7ff);
		fp->attributes = parse_uac_endpoint_attributes(chip, alts, protocol, iface_no);
		fp->clock = clock;
		fp->chmap = convert_chmap(num_channels, chconfig, protocol);

		/* some quirks for attributes here */

		@@ -698,12 +697,16 @@ int snd_usb_parse_audio_interface(struct snd_usb_audio *chip, int iface_no)
		/* ok, let's parse further... */
		if (snd_usb_parse_audio_format(chip, fp, format, fmt, stream) < 0) {
		kfree(fp->rate_table);
		kfree(fp->chmap);
		kfree(fp);
		fp = NULL;
		continue;
		}

		/* Create chmap */
		if (fp->channels != num_channels)
		chconfig = 0;
		fp->chmap = convert_chmap(fp->channels, chconfig, protocol);

		snd_printdd(KERN_INFO "%d:%u:%d: add audio endpoint %#x\n", dev->devnum, iface_no, altno, fp->endpoint);
		err = snd_usb_add_audio_stream(chip, stream, fp);
		if (err < 0) {

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