Commit 0cafae90 authored Feb 14, 2020 by Takashi Iwai Committed by Greg Kroah-Hartman Oct 01, 2020

ALSA: usb-audio: Don't create a mixer element with bogus volume range

[ Upstream commit e9a0ef0b5ddcbc0d56c65aefc0f18d16e6f71207 ]

Some USB-audio descriptors provide a bogus volume range (e.g. volume
min and max are identical), which confuses user-space.
This patch makes the driver skipping such a control element.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206221
Link: https://lore.kernel.org/r/20200214144928.23628-1-tiwai@suse.de


Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent ac6724d4

sound/usb/mixer.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -1699,6 +1699,16 @@ static void __build_feature_ctl(struct usb_mixer_interface *mixer,
		/* get min/max values */
		get_min_max_with_quirks(cval, 0, kctl);

		/* skip a bogus volume range */
		if (cval->max <= cval->min) {
		usb_audio_dbg(mixer->chip,
		"[%d] FU [%s] skipped due to invalid volume\n",
		cval->head.id, kctl->id.name);
		snd_ctl_free_one(kctl);
		return;
		}


		if (control == UAC_FU_VOLUME) {
		check_mapped_dB(map, cval);
		if (cval->dBmin < cval->dBmax \|\| !cval->initialized) {