ALSA: usb-audio: parse UAC2 sample rate ranges correctly (67c10366) · Commits · 戴 / test

sound/usb/format.c

+74 −18

Original line number	Diff line number	Diff line
		@@ -205,6 +205,60 @@ static int parse_audio_format_rates_v1(struct snd_usb_audio *chip, struct audiof
		return 0;
		}

		/*
		* 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);

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