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Commit 82896f29 authored by Trent Piepho's avatar Trent Piepho Committed by Mauro Carvalho Chehab
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V4L/DVB (6184): cx88-alsa: Make volume control stereo 



Use the balance control to make the mono volume control stereo.

Note that full range isn't supported.  The balance control attenuates one
channel by 0 to -63 dB, and the volume control provides additional attenuation
to both channels by another 0 to -63 dB.

So the channel with the most attenuation has a range of 0 to -126 dB, while
the other channel only has a range of 0 to -63 dB.  ALSA volume controls don't
appear to support this concept.  I just limited the range to 0 to -63 total.
Once you get to -63 dB, you're already at silence, so additional attenuation
is pretty much pointless anyway.

Signed-off-by: default avatarTrent Piepho <xyzzy@speakeasy.org>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
parent 6fcecce7

drivers/media/video/cx88/cx88-alsa.c

+37 −24
Original line number Diff line number Diff line
@@ -552,7 +552,7 @@ static int snd_cx88_capture_volume_info(struct snd_kcontrol *kcontrol, 
					struct snd_ctl_elem_info *info)

{

	info->type = SNDRV_CTL_ELEM_TYPE_INTEGER;

	info->count = 1;

	info->count = 2;

	info->value.integer.min = 0;

	info->value.integer.max = 0x3f;
@@ -565,8 +565,12 @@ static int snd_cx88_capture_volume_get(struct snd_kcontrol *kcontrol, 
{

	snd_cx88_card_t *chip = snd_kcontrol_chip(kcontrol);

	struct cx88_core *core=chip->core;

	int vol = 0x3f - (cx_read(AUD_VOL_CTL) & 0x3f),

	    bal = cx_read(AUD_BAL_CTL);



	value->value.integer.value[0] = 0x3f - (cx_read(AUD_VOL_CTL) & 0x3f);

	value->value.integer.value[(bal & 0x40) ? 0 : 1] = vol;

	vol -= (bal & 0x3f);

	value->value.integer.value[(bal & 0x40) ? 1 : 0] = vol < 0 ? 0 : vol;



	return 0;

}
@@ -577,19 +581,31 @@ static int snd_cx88_capture_volume_put(struct snd_kcontrol *kcontrol, 
{

	snd_cx88_card_t *chip = snd_kcontrol_chip(kcontrol);

	struct cx88_core *core=chip->core;

	int v;

	u32 old_control;

	int v, b;

	int changed = 0;

	u32 old;



	b = value->value.integer.value[1] - value->value.integer.value[0];

	if (b < 0) {

	    v = 0x3f - value->value.integer.value[0];

	    b = (-b) | 0x40;

	} else {

	    v = 0x3f - value->value.integer.value[1];

	}

	/* Do we really know this will always be called with IRQs on? */

	spin_lock_irq(&chip->reg_lock);



	old_control = 0x3f - (cx_read(AUD_VOL_CTL) & 0x3f);

	v = 0x3f - (value->value.integer.value[0] & 0x3f);

	cx_andor(AUD_VOL_CTL, 0x3f, v);



	old = cx_read(AUD_VOL_CTL);

	if (v != (old & 0x3f)) {

	    cx_write(AUD_VOL_CTL, (old & ~0x3f) | v);

	    changed = 1;

	}

	if (cx_read(AUD_BAL_CTL) != b) {

	    cx_write(AUD_BAL_CTL, b);

	    changed = 1;

	}

	spin_unlock_irq(&chip->reg_lock);



	return v != old_control;

	return changed;

}



static struct snd_kcontrol_new snd_cx88_capture_volume = {
@@ -746,17 +762,12 @@ static int __devinit cx88_audio_initdev(struct pci_dev *pci, 
		return (err);



	err = snd_cx88_pcm(chip, 0, "CX88 Digital");



	if (err < 0) {

		snd_card_free(card);

		return (err);

	}

	if (err < 0)

		goto error;



	err = snd_ctl_add(card, snd_ctl_new1(&snd_cx88_capture_volume, chip));

	if (err < 0) {

		snd_card_free(card);

		return (err);

	}

	if (err < 0)

		goto error;



	strcpy (card->driver, "CX88x");

	sprintf(card->shortname, "Conexant CX%x", pci->device);
@@ -768,14 +779,16 @@ static int __devinit cx88_audio_initdev(struct pci_dev *pci, 
	       card->driver,devno);



	err = snd_card_register(card);

	if (err < 0) {

		snd_card_free(card);

		return (err);

	}

	if (err < 0)

		goto error;

	pci_set_drvdata(pci,card);



	devno++;

	return 0;



error:

	snd_card_free(card);

	return err;

}

/*

 * ALSA destructor