ALSA: usb-audio: Filter out unsupported sample rates on Focusrite devices

	return false;

}

/*

 * Many Focusrite devices supports a limited set of sampling rates per

 * altsetting. Maximum rate is exposed in the last 4 bytes of Format Type

 * descriptor which has a non-standard bLength = 10.

 */

static bool focusrite_valid_sample_rate(struct snd_usb_audio *chip,

					struct audioformat *fp,

					unsigned int rate)

{

	struct usb_interface *iface;

	struct usb_host_interface *alts;

	unsigned char *fmt;

	unsigned int max_rate;

	iface = usb_ifnum_to_if(chip->dev, fp->iface);

	if (!iface)

		return true;

	alts = &iface->altsetting[fp->altset_idx];

	fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen,

				      NULL, UAC_FORMAT_TYPE);

	if (!fmt)

		return true;

	if (fmt[0] == 10) { /* bLength */

		max_rate = combine_quad(&fmt[6]);

		/* Validate max rate */

		if (max_rate != 48000 &&

		    max_rate != 96000 &&

		    max_rate != 192000 &&

		    max_rate != 384000) {

			usb_audio_info(chip,

				"%u:%d : unexpected max rate: %u\n",

				fp->iface, fp->altsetting, max_rate);

			return true;

		}

		return rate <= max_rate;

	}

	return true;

}

/*

 * 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

			    !s1810c_valid_sample_rate(fp, rate))

				goto skip_rate;

			/* Filter out invalid rates on Focusrite devices */

			if (USB_ID_VENDOR(chip->usb_id) == 0x1235 &&

			    !focusrite_valid_sample_rate(chip, fp, rate))

				goto skip_rate;

			if (fp->rate_table)

				fp->rate_table[nr_rates] = rate;

			if (!fp->rate_min || rate < fp->rate_min)