ALSA: virtuoso: remove non-working controls on Essence ST Deluxe

On the Xonar Essence ST Deluxe, remove all mixer controls that would
require I2C communication with the third DAC, which does not work
because of an addressing conflict with the CS2000 chip.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/oxygen/xonar_pcm179x.c

@@ -228,6 +228,7 @@ struct xonar_pcm179x {
 	s8 hp_gain_offset;
 	bool has_cs2000;
 	u8 cs2000_regs[0x1f];
+	bool broken_i2c;
 };
 
 struct xonar_hdav {
@@ -462,6 +463,7 @@ static void xonar_st_init(struct oxygen *chip)
 	data->generic.anti_pop_delay = 100;
 	data->has_cs2000 = 1;
 	data->cs2000_regs[CS2000_FUN_CFG_1] = CS2000_REF_CLK_DIV_1;
+	data->broken_i2c = true;
 
 	oxygen_write16(chip, OXYGEN_I2S_A_FORMAT,
 		       OXYGEN_RATE_48000 | OXYGEN_I2S_FORMAT_I2S |
@@ -980,16 +982,29 @@ static int xonar_d2_control_filter(struct snd_kcontrol_new *template)
 	return 0;
 }
 
+static int xonar_st_h6_control_filter(struct snd_kcontrol_new *template)
+{
+	if (!strncmp(template->name, "Master Playback ", 16))
+		/* no volume/mute, as I²C to the third DAC does not work */
+		return 1;
+	return 0;
+}
+
 static int add_pcm1796_controls(struct oxygen *chip)
 {
+	struct xonar_pcm179x *data = chip->model_data;
 	int err;
 
-	err = snd_ctl_add(chip->card, snd_ctl_new1(&rolloff_control, chip));
-	if (err < 0)
-		return err;
-	err = snd_ctl_add(chip->card, snd_ctl_new1(&os_128_control, chip));
-	if (err < 0)
-		return err;
+	if (!data->broken_i2c) {
+		err = snd_ctl_add(chip->card,
+				  snd_ctl_new1(&rolloff_control, chip));
+		if (err < 0)
+			return err;
+		err = snd_ctl_add(chip->card,
+				  snd_ctl_new1(&os_128_control, chip));
+		if (err < 0)
+			return err;
+	}
 	return 0;
 }
 
@@ -1208,6 +1223,7 @@ int __devinit get_xonar_pcm179x_model(struct oxygen *chip,
 			break;
 		case GPIO_DB_H6:
 			chip->model.shortname = "Xonar ST+H6";
+			chip->model.control_filter = xonar_st_h6_control_filter;
 			chip->model.dac_channels_pcm = 8;
 			chip->model.dac_channels_mixer = 8;
 			break;