summaryrefslogtreecommitdiff
path: root/sound
diff options
context:
space:
mode:
Diffstat (limited to 'sound')
-rw-r--r--sound/usb/format.c92
1 files changed, 74 insertions, 18 deletions
diff --git a/sound/usb/format.c b/sound/usb/format.c
index 8eccf17a4ac6..30364aba79cc 100644
--- a/sound/usb/format.c
+++ b/sound/usb/format.c
@@ -206,6 +206,60 @@ static int parse_audio_format_rates_v1(struct snd_usb_audio *chip, struct audiof
}
/*
+ * Helper function to walk the array of sample rate triplets reported by
+ * the device. The problem is that we need to parse whole array first to
+ * get to know how many sample rates we have to expect.
+ * Then fp->rate_table can be allocated and filled.
+ */
+static int parse_uac2_sample_rate_range(struct audioformat *fp, int nr_triplets,
+ const unsigned char *data)
+{
+ int i, nr_rates = 0;
+
+ fp->rates = fp->rate_min = fp->rate_max = 0;
+
+ for (i = 0; i < nr_triplets; i++) {
+ int min = combine_quad(&data[2 + 12 * i]);
+ int max = combine_quad(&data[6 + 12 * i]);
+ int res = combine_quad(&data[10 + 12 * i]);
+ int rate;
+
+ if ((max < 0) || (min < 0) || (res < 0) || (max < min))
+ continue;
+
+ /*
+ * for ranges with res == 1, we announce a continuous sample
+ * rate range, and this function should return 0 for no further
+ * parsing.
+ */
+ if (res == 1) {
+ fp->rate_min = min;
+ fp->rate_max = max;
+ fp->rates = SNDRV_PCM_RATE_CONTINUOUS;
+ return 0;
+ }
+
+ for (rate = min; rate <= max; rate += res) {
+ if (fp->rate_table)
+ fp->rate_table[nr_rates] = rate;
+ if (!fp->rate_min || rate < fp->rate_min)
+ fp->rate_min = rate;
+ if (!fp->rate_max || rate > fp->rate_max)
+ fp->rate_max = rate;
+ fp->rates |= snd_pcm_rate_to_rate_bit(rate);
+
+ nr_rates++;
+
+ /* avoid endless loop */
+ if (res == 0)
+ break;
+ }
+ }
+
+ return nr_rates;
+}
+
+/*
* parse the format descriptor and stores the possible sample rates
* on the audioformat table (audio class v2).
*/
@@ -215,7 +269,7 @@ static int parse_audio_format_rates_v2(struct snd_usb_audio *chip,
{
struct usb_device *dev = chip->dev;
unsigned char tmp[2], *data;
- int i, nr_rates, data_size, ret = 0;
+ int nr_triplets, data_size, ret = 0;
int clock = snd_usb_clock_find_source(chip, chip->ctrl_intf, fp->clock);
if (clock < 0) {
@@ -237,8 +291,8 @@ static int parse_audio_format_rates_v2(struct snd_usb_audio *chip,
goto err;
}
- nr_rates = (tmp[1] << 8) | tmp[0];
- data_size = 2 + 12 * nr_rates;
+ nr_triplets = (tmp[1] << 8) | tmp[0];
+ data_size = 2 + 12 * nr_triplets;
data = kzalloc(data_size, GFP_KERNEL);
if (!data) {
ret = -ENOMEM;
@@ -259,26 +313,28 @@ static int parse_audio_format_rates_v2(struct snd_usb_audio *chip,
goto err_free;
}
- fp->rate_table = kmalloc(sizeof(int) * nr_rates, GFP_KERNEL);
+ /* Call the triplet parser, and make sure fp->rate_table is NULL.
+ * We just use the return value to know how many sample rates we
+ * will have to deal with. */
+ kfree(fp->rate_table);
+ fp->rate_table = NULL;
+ fp->nr_rates = parse_uac2_sample_rate_range(fp, nr_triplets, data);
+
+ if (fp->nr_rates == 0) {
+ /* SNDRV_PCM_RATE_CONTINUOUS */
+ ret = 0;
+ goto err_free;
+ }
+
+ fp->rate_table = kmalloc(sizeof(int) * fp->nr_rates, GFP_KERNEL);
if (!fp->rate_table) {
ret = -ENOMEM;
goto err_free;
}
- fp->nr_rates = 0;
- fp->rate_min = fp->rate_max = 0;
-
- for (i = 0; i < nr_rates; i++) {
- int rate = combine_quad(&data[2 + 12 * i]);
-
- fp->rate_table[fp->nr_rates] = rate;
- if (!fp->rate_min || rate < fp->rate_min)
- fp->rate_min = rate;
- if (!fp->rate_max || rate > fp->rate_max)
- fp->rate_max = rate;
- fp->rates |= snd_pcm_rate_to_rate_bit(rate);
- fp->nr_rates++;
- }
+ /* Call the triplet parser again, but this time, fp->rate_table is
+ * allocated, so the rates will be stored */
+ parse_uac2_sample_rate_range(fp, nr_triplets, data);
err_free:
kfree(data);