[ALSA] fix parsing of mixer unit descriptors

USB generic driver
MU descriptor parsing code completely rewritten; the old code confused
the number of input audio channel clusters and the number of input
channels.  Furthermore, check all bmControls bits so that mixer
controls are created even if the first output channel doesn't have
a control.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

1 files changed, 40 insertions, 19 deletions

diff --git a/sound/usb/usbmixer.c b/sound/usb/usbmixer.c
index 2155a25ad08d5c..f554be7b828f62 100644
--- a/sound/usb/usbmixer.c
+++ b/sound/usb/usbmixer.c
@@ -931,14 +931,14 @@ static int parse_audio_feature_unit(mixer_build_t *state, int unitid, unsigned c
  */
 
 static void build_mixer_unit_ctl(mixer_build_t *state, unsigned char *desc,
-				 int in_ch, int unitid)
+				 int in_pin, int in_ch, int unitid,
+				 usb_audio_term_t *iterm)
 {
 	usb_mixer_elem_info_t *cval;
-	unsigned int num_ins = desc[4];
-	unsigned int num_outs = desc[5 + num_ins];
+	unsigned int input_pins = desc[4];
+	unsigned int num_outs = desc[5 + input_pins];
 	unsigned int i, len;
 	snd_kcontrol_t *kctl;
-	usb_audio_term_t iterm;
 
 	if (check_ignored_ctl(state, unitid, 0))
 		return;
@@ -947,16 +947,13 @@ static void build_mixer_unit_ctl(mixer_build_t *state, unsigned char *desc,
 	if (! cval)
 		return;
 
-	if (check_input_term(state, desc[5 + in_ch], &iterm) < 0)
-		return;
-
 	cval->chip = state->chip;
 	cval->ctrlif = state->ctrlif;
 	cval->id = unitid;
 	cval->control = in_ch + 1; /* based on 1 */
 	cval->val_type = USB_MIXER_S16;
 	for (i = 0; i < num_outs; i++) {
-		if (check_matrix_bitmap(desc + 9 + num_ins, in_ch, i, num_outs)) {
+		if (check_matrix_bitmap(desc + 9 + input_pins, in_ch, i, num_outs)) {
 			cval->cmask |= (1 << i);
 			cval->channels++;
 		}
@@ -975,9 +972,9 @@ static void build_mixer_unit_ctl(mixer_build_t *state, unsigned char *desc,
 
 	len = check_mapped_name(state, unitid, 0, kctl->id.name, sizeof(kctl->id.name));
 	if (! len)
-		len = get_term_name(state, &iterm, kctl->id.name, sizeof(kctl->id.name), 0);
+		len = get_term_name(state, iterm, kctl->id.name, sizeof(kctl->id.name), 0);
 	if (! len)
-		len = sprintf(kctl->id.name, "Mixer Source %d", in_ch);
+		len = sprintf(kctl->id.name, "Mixer Source %d", in_ch + 1);
 	strlcat(kctl->id.name + len, " Volume", sizeof(kctl->id.name));
 
 	snd_printdd(KERN_INFO "[%d] MU [%s] ch = %d, val = %d/%d\n",
@@ -991,20 +988,44 @@ static void build_mixer_unit_ctl(mixer_build_t *state, unsigned char *desc,
  */
 static int parse_audio_mixer_unit(mixer_build_t *state, int unitid, unsigned char *desc)
 {
-	int num_ins, num_outs;
-	int i, err;
+	usb_audio_term_t iterm;
+	int input_pins, num_ins, num_outs;
+	int pin, ich, err;
 
-	if (desc[0] < 11 || ! (num_ins = desc[4]) || ! (num_outs = desc[5 + num_ins]))
+	if (desc[0] < 11 || ! (input_pins = desc[4]) || ! (num_outs = desc[5 + input_pins])) {
+		snd_printk(KERN_ERR "invalid MIXER UNIT descriptor %d\n", unitid);
 		return -EINVAL;
+	}
+	/* no bmControls field (e.g. Maya44) -> ignore */
+	if (desc[0] <= 10 + input_pins) {
+		snd_printdd(KERN_INFO "MU %d has no bmControls field\n", unitid);
+		return 0;
+	}
 
-	for (i = 0; i < num_ins; i++) {
-		err = parse_audio_unit(state, desc[5 + i]);
+	num_ins = 0;
+	ich = 0;
+	for (pin = 0; pin < input_pins; pin++) {
+		err = parse_audio_unit(state, desc[5 + pin]);
+		if (err < 0)
+			return err;
+		err = check_input_term(state, desc[5 + pin], &iterm);
 		if (err < 0)
 			return err;
-		/* some devices (e.g. Maya44) omit the bitmap */
-		if (desc[0] > 11 &&
-		    check_matrix_bitmap(desc + 9 + num_ins, i, 0, num_outs))
-			build_mixer_unit_ctl(state, desc, i, unitid);
+		num_ins += iterm.channels;
+		for (; ich < num_ins; ++ich) {
+			int och, ich_has_controls = 0;
+
+			for (och = 0; och < num_outs; ++och) {
+				if (check_matrix_bitmap(desc + 9 + input_pins,
+							ich, och, num_outs)) {
+					ich_has_controls = 1;
+					break;
+				}
+			}
+			if (ich_has_controls)
+				build_mixer_unit_ctl(state, desc, pin, ich,
+						     unitid, &iterm);
+		}
 	}
 	return 0;
 }