1 files changed, 93 insertions, 0 deletions

diff --git a/sound/usb/format.c b/sound/usb/format.c
index 3bfead393aa3..3348032daa16 100644
--- a/sound/usb/format.c
+++ b/sound/usb/format.c
@@ -417,6 +417,97 @@ static int line6_parse_audio_format_rates_quirk(struct snd_usb_audio *chip,
 	return -ENODEV;
 }
 
+/* check whether the given altsetting is supported for the already set rate */
+static bool check_valid_altsetting_v2v3(struct snd_usb_audio *chip, int iface,
+					int altsetting)
+{
+	struct usb_device *dev = chip->dev;
+	__le64 raw_data = 0;
+	u64 data;
+	int err;
+
+	/* we assume 64bit is enough for any altsettings */
+	if (snd_BUG_ON(altsetting >= 64 - 8))
+		return false;
+
+	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
+			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+			      UAC2_AS_VAL_ALT_SETTINGS << 8,
+			      iface, &raw_data, sizeof(raw_data));
+	if (err < 0)
+		return false;
+
+	data = le64_to_cpu(raw_data);
+	/* first byte contains the bitmap size */
+	if ((data & 0xff) * 8 < altsetting)
+		return false;
+	if (data & (1ULL << (altsetting + 8)))
+		return true;
+
+	return false;
+}
+
+/*
+ * Validate each sample rate with the altsetting
+ * Rebuild the rate table if only partial values are valid
+ */
+static int validate_sample_rate_table_v2v3(struct snd_usb_audio *chip,
+					   struct audioformat *fp,
+					   int clock)
+{
+	struct usb_device *dev = chip->dev;
+	unsigned int *table;
+	unsigned int nr_rates;
+	unsigned int rate_min = 0x7fffffff;
+	unsigned int rate_max = 0;
+	unsigned int rates = 0;
+	int i, err;
+
+	table = kcalloc(fp->nr_rates, sizeof(*table), GFP_KERNEL);
+	if (!table)
+		return -ENOMEM;
+
+	/* clear the interface altsetting at first */
+	usb_set_interface(dev, fp->iface, 0);
+
+	nr_rates = 0;
+	for (i = 0; i < fp->nr_rates; i++) {
+		err = snd_usb_set_sample_rate_v2v3(chip, fp, clock,
+						   fp->rate_table[i]);
+		if (err < 0)
+			continue;
+
+		if (check_valid_altsetting_v2v3(chip, fp->iface, fp->altsetting)) {
+			table[nr_rates++] = fp->rate_table[i];
+			if (rate_min > fp->rate_table[i])
+				rate_min = fp->rate_table[i];
+			if (rate_max < fp->rate_table[i])
+				rate_max = fp->rate_table[i];
+			rates |= snd_pcm_rate_to_rate_bit(fp->rate_table[i]);
+		}
+	}
+
+	if (!nr_rates) {
+		usb_audio_dbg(chip,
+			      "No valid sample rate available for %d:%d, assuming a firmware bug\n",
+			      fp->iface, fp->altsetting);
+		nr_rates = fp->nr_rates; /* continue as is */
+	}
+
+	if (fp->nr_rates == nr_rates) {
+		kfree(table);
+		return 0;
+	}
+
+	kfree(fp->rate_table);
+	fp->rate_table = table;
+	fp->nr_rates = nr_rates;
+	fp->rate_min = rate_min;
+	fp->rate_max = rate_max;
+	fp->rates = rates;
+	return 0;
+}
+
 /*
  * parse the format descriptor and stores the possible sample rates
  * on the audioformat table (audio class v2 and v3).
@@ -509,6 +600,8 @@ static int parse_audio_format_rates_v2v3(struct snd_usb_audio *chip,
 	 * allocated, so the rates will be stored */
 	parse_uac2_sample_rate_range(chip, fp, nr_triplets, data);
 
+	ret = validate_sample_rate_table_v2v3(chip, fp, clock);
+
 err_free:
 	kfree(data);
 err: