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Commit 8c55af3f authored by Eldad Zack's avatar Eldad Zack Committed by Takashi Iwai
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ALSA: usb-audio: UAC2: try to find and switch to valid clock 



If a selector is available on a device, it may be pointing to a
clock source which is currently invalid.
If there is a valid clock source which can be selected, switch
to it.

Signed-off-by: default avatarEldad Zack <eldad@fogrefinery.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 06ffc1eb

sound/usb/clock.c

+66 −3
Original line number Diff line number Diff line
@@ -99,6 +99,41 @@ static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_i 
	return buf;

}



static int uac_clock_selector_set_val(struct snd_usb_audio *chip, int selector_id,

					unsigned char pin)

{

	int ret;



	ret = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),

			      UAC2_CS_CUR,

			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,

			      UAC2_CX_CLOCK_SELECTOR << 8,

			      snd_usb_ctrl_intf(chip) | (selector_id << 8),

			      &pin, sizeof(pin));

	if (ret < 0)

		return ret;



	if (ret != sizeof(pin)) {

		snd_printk(KERN_ERR

			"usb-audio:%d: setting selector (id %d) unexpected length %d\n",

			chip->dev->devnum, selector_id, ret);

		return -EINVAL;

	}



	ret = uac_clock_selector_get_val(chip, selector_id);

	if (ret < 0)

		return ret;



	if (ret != pin) {

		snd_printk(KERN_ERR

			"usb-audio:%d: setting selector (id %d) to %x failed (current: %d)\n",

			chip->dev->devnum, selector_id, pin, ret);

		return -EINVAL;

	}



	return ret;

}



static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)

{

	int err;
@@ -161,7 +196,7 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip, 


	selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);

	if (selector) {

		int ret;

		int ret, i, cur;



		/* the entity ID we are looking for is a selector.

		 * find out what it currently selects */
@@ -179,8 +214,35 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip, 
			return -EINVAL;

		}



		return __uac_clock_find_source(chip, selector->baCSourceID[ret-1],

		cur = ret;

		ret = __uac_clock_find_source(chip, selector->baCSourceID[ret - 1],

					       visited, validate);

		if (!validate || ret > 0)

			return ret;



		/* The current clock source is invalid, try others. */

		for (i = 1; i <= selector->bNrInPins; i++) {

			int err;



			if (i == cur)

				continue;



			ret = __uac_clock_find_source(chip, selector->baCSourceID[i - 1],

				visited, true);

			if (ret < 0)

				continue;



			err = uac_clock_selector_set_val(chip, entity_id, i);

			if (err < 0)

				continue;



			snd_printk(KERN_INFO

				"usb-audio:%d: found and selected valid clock source %d\n",

				chip->dev->devnum, ret);

			return ret;

		}



		return -ENXIO;

	}



	/* FIXME: multipliers only act as pass-thru element for now */
@@ -284,8 +346,9 @@ static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface, 
	struct usb_device *dev = chip->dev;

	__le32 data;

	int err, cur_rate, prev_rate;

	int clock = snd_usb_clock_find_source(chip, fmt->clock, true);

	int clock;



	clock = snd_usb_clock_find_source(chip, fmt->clock, true);

	if (clock < 0)

		return clock;