tlv: improve raw value range handling

This makes snd_tlv_convert_from_dB() more robust wrt DB_SCALE type
by consistently parsing the ranges.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 17 insertions, 22 deletions

diff --git a/src/control.c b/src/control.c
index a677b59..4a7666f 100644
--- a/src/control.c
+++ b/src/control.c
@@ -630,40 +630,35 @@ static int tlv_from_dB_range(unsigned int *tlv, long rangemin, long rangemax,
 			     long db_gain, long *value, int xdir)
 {
 	unsigned int pos, len;
-	long dbmin, dbmax, prev_rangemax;
+	long dbmin, dbmax, prev_submax;
 
 	len = int_index(tlv[1]);
-	if (len > MAX_TLV_RANGE_SIZE)
-		return -EINVAL;
-	if (snd_tlv_get_dB_range(tlv, rangemin, rangemax, &dbmin, &dbmax))
+	if (len < 6 || len > MAX_TLV_RANGE_SIZE)
 		return -EINVAL;
-	if (db_gain <= dbmin) {
-		*value = rangemin;
-		return 0;
-	} else if (db_gain >= dbmax) {
-		*value = rangemax;
-		return 0;
-	}
 	pos = 2;
-	prev_rangemax = 0;
+	prev_submax = 0;
 	while (pos + 4 <= len) {
-		rangemin = (int)tlv[pos++];
-		rangemax = (int)tlv[pos++];
-		if (!snd_tlv_get_dB_range(tlv + pos, rangemin, rangemax,
+		long submin = (int)tlv[pos++];
+		long submax = (int)tlv[pos++];
+		if (rangemax < submax)
+			submax = rangemax;
+		if (!snd_tlv_get_dB_range(tlv + pos + 2, submin, submax,
 					  &dbmin, &dbmax) &&
 		    db_gain >= dbmin && db_gain <= dbmax)
-			return snd_tlv_convert_from_dB(tlv + pos,
-						       rangemin, rangemax,
+			return snd_tlv_convert_from_dB(tlv + pos + 2,
+						       submin, submax,
 						       db_gain, value, xdir);
 		else if (db_gain < dbmin) {
-			*value = xdir ? rangemin : prev_rangemax;
+			*value = xdir > 0 || pos == 2 ? submin : prev_submax;
 			return 0;
 		}
-		prev_rangemax = rangemax;
-		pos++;
-		pos += int_index(tlv[pos]) + 1;
+		prev_submax = submax;
+		if (rangemax == submax)
+			break;
+		pos += int_index(tlv[pos + 3]) + 4;
 	}
-	return -EINVAL;
+	*value = prev_submax;
+	return 0;
 }
 
 static void _tlv_from_dB_minmax(long rangemin, long rangemax,