diff mbox series

ALSA: usb-audio: Add DJM750 to Pioneer mixer quirk

Message ID 20210128160338.dac4vrj7wjiykcxm@base.nu
State Superseded
Headers show
Series ALSA: usb-audio: Add DJM750 to Pioneer mixer quirk | expand

Commit Message

Olivia Mackintosh Jan. 28, 2021, 4:03 p.m. UTC 
This allows for N different devices to use the pioneer mixer quirk for
setting capture/record type and recording level. The impementation has
not changed much with the exception of an additional mask on
private_value to allow storing of a device index:
	DEVICE MASK	0xff000000
	GROUP_MASK	0x00ff0000
	VALUE_MASK	0x0000ffff

There is perhaps room for removing the duplication in the lookup tables
(name, wValue, wIndex) and deriving these. See the code header comment
to understand how this can be achieved.

Feedback is very much appreciated as I'm not the most proficient C
programmer but am learning as I go.

Signed-off-by: Olivia Mackintosh <livvy@base.nu>
---
 sound/usb/mixer_quirks.c | 195 +++++++++++++++++++++++++++++----------
 1 file changed, 148 insertions(+), 47 deletions(-)

Comments

František Kučera Feb. 1, 2021, 3:34 p.m. UTC | #1 
Dne 29. 01. 21 v 15:09 Fabian Lesniak napsal(a):
> In general, I'm wondering whether it is a good way to implement more and more
> Pioneer devices in such a hard coded way. mixer_quirks.c already has >3k LOC,
> and the 900NXS2 support will add at least 100 more if written in the same
> scheme. It may be good to either dynamically create controls depending on the
> model or move pioneer support to an extra file.

The original idea was to reduce complexity rather than lines of code and keep it straightforward without many IF branching and special cases.

Maybe more data/configuration (declared arrays) can be shared among multiple devices – like the capture_level.

Does not the DJM750 support also mapping of MIC, AUX and REC OUT or any playback mapping? If it would, more configuration might be shared. And is it DJM-750MK2 or DJM-750-K? At least the specification of DJM-750-K talks about a sound card with 4 stereo inputs and 4 stereo outputs.

Does anybody know/have other DJM hardware? Does it use the same codes (wValue/wIndex)?

Franta
Fabian Lesniak Feb. 1, 2021, 9:37 p.m. UTC | #2 
Hi Franta,

I've just submitted mixer quirks for the 900NXS2, following the design of 
Olivia and you. Seems quite clean, but if anyone comes up with a clever idea 
on how to share code between the channel arrays, I'd highly appreciate that. 
My experiments so far turned out quite complex: I thought about adding flags 
like "DEVICE_HAS_DIGITAL", "DEVICE_HAS_AUX" etc. which are evaluated during 
control creation and usage. The code became unreadable and complex, so I 
ditched that idea. Creating the controls arrays dynamically would maybe help.

The 900NXS2 uses the same wValue/wIndex as your 250Mk2, just expanded to five 
channels. It does not allow to set playback channels via USB, that can only be 
done in hardware using the input source knob. I guess that is same for the 
DJM-700. The 900NXS2 allows querying the currently selected playback channel 
though, but I think this is of no great use so I did not implement it in this 
patch (although it was in my original draft from last year: https://
gist.github.com/flesniak/074ab23bbc833663b782f44174eae6a4). If you think it's 
worth it, I could have a look at that again.

Cheers
Fabian

Am Montag, 1. Februar 2021, 16:34:29 CET schrieb František Kučera:
> Dne 29. 01. 21 v 15:09 Fabian Lesniak napsal(a):
> > In general, I'm wondering whether it is a good way to implement more and
> > more Pioneer devices in such a hard coded way. mixer_quirks.c already has
> > >3k LOC, and the 900NXS2 support will add at least 100 more if written in
> > the same scheme. It may be good to either dynamically create controls
> > depending on the model or move pioneer support to an extra file.
> 
> The original idea was to reduce complexity rather than lines of code and
> keep it straightforward without many IF branching and special cases.
> 
> Maybe more data/configuration (declared arrays) can be shared among multiple
> devices – like the capture_level.
> 
> Does not the DJM750 support also mapping of MIC, AUX and REC OUT or any
> playback mapping? If it would, more configuration might be shared. And is
> it DJM-750MK2 or DJM-750-K? At least the specification of DJM-750-K talks
> about a sound card with 4 stereo inputs and 4 stereo outputs.
> 
> Does anybody know/have other DJM hardware? Does it use the same codes
> (wValue/wIndex)?
> 
> Franta
Olivia Mackintosh Feb. 2, 2021, 1:08 a.m. UTC | #3 
Hi all,

I did a little exploration of this before too and though I would share my
notes FWIW.

Some things we might be able to do right off the bat:
	1. Move wIndex from each item into the control group:
>		struct snd_pioneer_djm_option_group {
>			const char *name;
>			const struct snd_pioneer_djm_option *options;
>			const size_t count;
>			const u16 default_value;
>			const u16 windex;
>		};
>
	2. Generate labels based on wValue perhaps in the fashion of
		where each case is an enum or define (e.g. PHONO = 0x3):
>		static char *snd_pioneer_djm_get_label(u8 input_type) {
>		      switch (input_type) {
>		      case LINE:      return "Control Tone LINE\0";
>		      case CDLINE:    return "Control Tone CD/LINE\0";
>		      case PHONO:     return "Control Tone PHONO\0";
>		      case PFADER:    return "Post Fader\0";
>		      case XFADERA:   return "Cross Fader A\0";
>		      case XFADERB:   return "Cross Fader B\0";
>		      case MIC:       return "Mic\0";
>		      case RECOUT:    return "Rec Out\0";
>		      case AUX:       return "Aux\0";
>		      case NONE:      return "None\0";
>		      case PFADERCH1: return "Post Fader CH1\0";
>		      case PFADERCH2: return "Post Fader CH2\0";
>		      default:	return "\0"; // 'EINVAL'
>		};
>}	

This should get us 90% to where we need to be. I originally had lots of
huge code snippets that I were going to send but I think this is more
readable!

Other wildcard ideas I explored:
	1. Bitmask of values stored in u32 private_data. This could work
		since it only takes up 12bits but it seems like an abuse of
		private_data's intended function and it feels like the
		unwrapping process would be somewhat length and messy.

		I think this is similar to your idea Fabian.

---

Maybe these notes will help provide some inspiration or something.
If I have the time I'll pick up from here tomorrow. Comments/input/
different ideas very welcome :).

Kindest regards,
Olivia


On Mon, Feb 01, 2021 at 10:37:21PM +0100, Fabian Lesniak wrote:
> Hi Franta,
> 
> I've just submitted mixer quirks for the 900NXS2, following the design of 
> Olivia and you. Seems quite clean, but if anyone comes up with a clever idea 
> on how to share code between the channel arrays, I'd highly appreciate that. 
> My experiments so far turned out quite complex: I thought about adding flags 
> like "DEVICE_HAS_DIGITAL", "DEVICE_HAS_AUX" etc. which are evaluated during 
> control creation and usage. The code became unreadable and complex, so I 
> ditched that idea. Creating the controls arrays dynamically would maybe help.
> 
> The 900NXS2 uses the same wValue/wIndex as your 250Mk2, just expanded to five 
> channels. It does not allow to set playback channels via USB, that can only be 
> done in hardware using the input source knob. I guess that is same for the 
> DJM-700. The 900NXS2 allows querying the currently selected playback channel 
> though, but I think this is of no great use so I did not implement it in this 
> patch (although it was in my original draft from last year: https://
> gist.github.com/flesniak/074ab23bbc833663b782f44174eae6a4). If you think it's 
> worth it, I could have a look at that again.
> 
> Cheers
> Fabian
> 
> Am Montag, 1. Februar 2021, 16:34:29 CET schrieb František Kučera:
> > Dne 29. 01. 21 v 15:09 Fabian Lesniak napsal(a):
> > > In general, I'm wondering whether it is a good way to implement more and
> > > more Pioneer devices in such a hard coded way. mixer_quirks.c already has
> > > >3k LOC, and the 900NXS2 support will add at least 100 more if written in
> > > the same scheme. It may be good to either dynamically create controls
> > > depending on the model or move pioneer support to an extra file.
> > 
> > The original idea was to reduce complexity rather than lines of code and
> > keep it straightforward without many IF branching and special cases.
> > 
> > Maybe more data/configuration (declared arrays) can be shared among multiple
> > devices – like the capture_level.
> > 
> > Does not the DJM750 support also mapping of MIC, AUX and REC OUT or any
> > playback mapping? If it would, more configuration might be shared. And is
> > it DJM-750MK2 or DJM-750-K? At least the specification of DJM-750-K talks
> > about a sound card with 4 stereo inputs and 4 stereo outputs.
> > 
> > Does anybody know/have other DJM hardware? Does it use the same codes
> > (wValue/wIndex)?
> > 
> > Franta
> 
>
diff mbox series

Patch

diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index abad1d61a536..8518691509d9 100644
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -2603,28 +2603,68 @@  static int snd_bbfpro_controls_create(struct usb_mixer_interface *mixer)
 }
 
 /*
- * Pioneer DJ DJM-250MK2 and maybe other DJM models
+ * Pioneer DJ DJM Mixers
  *
- * For playback, no duplicate mapping should be set.
- * There are three mixer stereo channels (CH1, CH2, AUX)
- * and three stereo sources (Playback 1-2, Playback 3-4, Playback 5-6).
- * Each channel should be mapped just once to one source.
- * If mapped multiple times, only one source will play on given channel
- * (sources are not mixed together).
+ * These devices generally have options for soft-switching the playback and
+ * capture sources in addition to the recording level. Although different
+ * devices have different configurations, there seems to be canonical values
+ * for specific capture/playback types:
  *
- * For recording, duplicate mapping is OK. We will get the same signal multiple times.
+ * 	Capture 			| Playback
+ * 	================================|===========
+ * 	Control Tone Line	0x00	| Ch1	0x00
+ * 	Control Tone CD/Line	0x01	| Ch2	0x01
+ * 	Control Tone Phono	0x03	| Aux	0x04
+ * 	Post Fader		0x06	|
+ * 	Cross Fader A		0x07	|
+ * 	Cross Fader B		0x08	|
+ * 	Mic			0x09	|
+ * 	Aux			0x0d	|
+ * 	Rec_Out			0x0a	|
+ * 	None			0x0f	|
+ * 	Ch1 Post Fader		0x11	|
+ * 	Ch2 Post Fader		0x12	|
  *
- * Channels 7-8 are in both directions fixed to FX SEND / FX RETURN.
+ * The wValue for configuring playback/capture type also contains the channel
+ * the input type should apply to:
+ * 	CHANNEL NUMBER	0xff00
+ * 	INPUT TYPE	0x00ff
+ * e.g. Channel 2 set to 'Control Tone Phono' will have wValue 0x0203
+ *
+ * The wIndex values are below:
+ * 	CAPTURE		0x8002
+ * 	CAPTURE LEVEL	0x8003
+ * 	PLAYBACK	0x8016
  *
- * See also notes in the quirks-table.h file.
  */
 
+#define snd_pioneer_djm_option_group_item(_name, suffix, _default_value) { \
+	.name = _name, \
+	.options = snd_pioneer_djm_options_##suffix, \
+	.count = ARRAY_SIZE(snd_pioneer_djm_options_##suffix), \
+	.default_value = _default_value }
+
+struct snd_pioneer_djm_device {
+	char *name;
+	const struct snd_pioneer_djm_option_group *controls;
+	const size_t ncontrols;
+};
+
 struct snd_pioneer_djm_option {
 	const u16 wIndex;
 	const u16 wValue;
 	const char *name;
 };
 
+struct snd_pioneer_djm_option_group {
+	const char *name;
+	const struct snd_pioneer_djm_option *options;
+	const size_t count;
+	const u16 default_value;
+};
+
+/* Common Options
+ */
 static const struct snd_pioneer_djm_option snd_pioneer_djm_options_capture_level[] = {
 	{ .name =  "-5 dB",                  .wValue = 0x0300, .wIndex = 0x8003 },
 	{ .name = "-10 dB",                  .wValue = 0x0200, .wIndex = 0x8003 },
@@ -2632,6 +2672,8 @@  static const struct snd_pioneer_djm_option snd_pioneer_djm_options_capture_level
 	{ .name = "-19 dB",                  .wValue = 0x0000, .wIndex = 0x8003 }
 };
 
+/* DJM250MK2 Options
+ */
 static const struct snd_pioneer_djm_option snd_pioneer_djm_options_capture_ch12[] = {
 	{ .name =  "CH1 Control Tone PHONO", .wValue = 0x0103, .wIndex = 0x8002 },
 	{ .name =  "CH1 Control Tone LINE",  .wValue = 0x0100, .wIndex = 0x8002 },
@@ -2682,20 +2724,8 @@  static const struct snd_pioneer_djm_option snd_pioneer_djm_options_playback_56[]
 	{ .name =  "AUX",                    .wValue = 0x0304, .wIndex = 0x8016 }
 };
 
-struct snd_pioneer_djm_option_group {
-	const char *name;
-	const struct snd_pioneer_djm_option *options;
-	const size_t count;
-	const u16 default_value;
-};
-
-#define snd_pioneer_djm_option_group_item(_name, suffix, _default_value) { \
-	.name = _name, \
-	.options = snd_pioneer_djm_options_##suffix, \
-	.count = ARRAY_SIZE(snd_pioneer_djm_options_##suffix), \
-	.default_value = _default_value }
 
-static const struct snd_pioneer_djm_option_group snd_pioneer_djm_option_groups[] = {
+static const struct snd_pioneer_djm_option_group snd_pioneer_djm250mk2_option_groups[] = {
 	snd_pioneer_djm_option_group_item("Master Capture Level Capture Switch", capture_level, 0),
 	snd_pioneer_djm_option_group_item("Capture 1-2 Capture Switch",          capture_ch12,  2),
 	snd_pioneer_djm_option_group_item("Capture 3-4 Capture Switch",          capture_ch34,  2),
@@ -2705,22 +2735,77 @@  static const struct snd_pioneer_djm_option_group snd_pioneer_djm_option_groups[]
 	snd_pioneer_djm_option_group_item("Playback 5-6 Playback Switch",        playback_56,   2)
 };
 
+
+/* DJM750 */
+static const struct snd_pioneer_djm_option snd_pioneer_djm_options_djm750_capture_ch1[] = {
+	{ .name =  "CH1 Control Tone LINE",  .wValue = 0x0100, .wIndex = 0x8002 },
+	{ .name =  "CH1 Control Tone PHONO", .wValue = 0x0103, .wIndex = 0x8002 },
+	{ .name =  "Post CH1 Fader",         .wValue = 0x0106, .wIndex = 0x8002 },
+	{ .name =  "Cross Fader A",          .wValue = 0x0107, .wIndex = 0x8002 },
+	{ .name =  "Cross Fader B",          .wValue = 0x0108, .wIndex = 0x8002 },
+};
+
+static const struct snd_pioneer_djm_option snd_pioneer_djm_options_djm750_capture_ch2[] = {
+	{ .name =  "CH2 Control Tone LINE",  .wValue = 0x0200, .wIndex = 0x8002 },
+	{ .name =  "CH2 Control Tone CDLINE",.wValue = 0x0201, .wIndex = 0x8002 },
+	{ .name =  "Post CH2 Fader",         .wValue = 0x0206, .wIndex = 0x8002 },
+	{ .name =  "Cross Fader A",          .wValue = 0x0207, .wIndex = 0x8002 },
+	{ .name =  "Cross Fader B",          .wValue = 0x0208, .wIndex = 0x8002 },
+};
+
+static const struct snd_pioneer_djm_option snd_pioneer_djm_options_djm750_capture_ch3[] = {
+	{ .name =  "CH3 Control Tone LINE",  .wValue = 0x0300, .wIndex = 0x8002 },
+	{ .name =  "CH3 Control Tone CDLINE",.wValue = 0x0301, .wIndex = 0x8002 },
+	{ .name =  "Post CH3 Fader",         .wValue = 0x0306, .wIndex = 0x8002 },
+	{ .name =  "Cross Fader A",          .wValue = 0x0307, .wIndex = 0x8002 },
+	{ .name =  "Cross Fader B",          .wValue = 0x0308, .wIndex = 0x8002 },
+};
+
+static const struct snd_pioneer_djm_option snd_pioneer_djm_options_djm750_capture_ch4[] = {
+	{ .name =  "CH4 Control Tone LINE",  .wValue = 0x0400, .wIndex = 0x8002 },
+	{ .name =  "CH4 Control Tone PHONO", .wValue = 0x0403, .wIndex = 0x8002 },
+	{ .name =  "Post CH4 Fader",         .wValue = 0x0406, .wIndex = 0x8002 },
+	{ .name =  "Cross Fader A",          .wValue = 0x0407, .wIndex = 0x8002 },
+	{ .name =  "Cross Fader B",          .wValue = 0x0408, .wIndex = 0x8002 },
+};
+
+static const struct snd_pioneer_djm_option_group snd_pioneer_djm750_option_groups[] = {
+	snd_pioneer_djm_option_group_item("Capture Level", capture_level, 0),
+	snd_pioneer_djm_option_group_item("CH1 Input", djm750_capture_ch1, 2),
+	snd_pioneer_djm_option_group_item("CH2 Input", djm750_capture_ch2, 2),
+	snd_pioneer_djm_option_group_item("CH3 Input", djm750_capture_ch3, 0),
+	snd_pioneer_djm_option_group_item("CH4 Input", djm750_capture_ch4, 0),
+};
+
+static const struct snd_pioneer_djm_device snd_pioneer_djm_devices[] = {
+	{ .name = "DJM-250Mk2", .controls = snd_pioneer_djm250mk2_option_groups, .ncontrols = 7},
+	{ .name = "DJM-750", .controls = snd_pioneer_djm750_option_groups, .ncontrols = 5}
+};
+
 // layout of the kcontrol->private_value:
 #define SND_PIONEER_DJM_VALUE_MASK 0x0000ffff
-#define SND_PIONEER_DJM_GROUP_MASK 0xffff0000
+#define SND_PIONEER_DJM_GROUP_MASK 0x00ff0000
+#define SND_PIONEER_DJM_DEVICE_MASK 0xff000000
 #define SND_PIONEER_DJM_GROUP_SHIFT 16
+#define SND_PIONEER_DJM_DEVICE_SHIFT 24
+
 
 static int snd_pioneer_djm_controls_info(struct snd_kcontrol *kctl, struct snd_ctl_elem_info *info)
 {
-	u16 group_index = kctl->private_value >> SND_PIONEER_DJM_GROUP_SHIFT;
+	unsigned long private_value = kctl->private_value;
+	u8 device_idx = (private_value & SND_PIONEER_DJM_DEVICE_MASK) >> SND_PIONEER_DJM_DEVICE_SHIFT;
+	u8 group_idx = (private_value & SND_PIONEER_DJM_GROUP_MASK) >> SND_PIONEER_DJM_GROUP_SHIFT;
+
+	const struct snd_pioneer_djm_device device = snd_pioneer_djm_devices[device_idx];
+
 	size_t count;
 	const char *name;
 	const struct snd_pioneer_djm_option_group *group;
 
-	if (group_index >= ARRAY_SIZE(snd_pioneer_djm_option_groups))
+	if (group_idx >= device.ncontrols)
 		return -EINVAL;
 
-	group = &snd_pioneer_djm_option_groups[group_index];
+	group = &device.controls[group_idx];
 	count = group->count;
 	if (info->value.enumerated.item >= count)
 		info->value.enumerated.item = count - 1;
@@ -2732,12 +2817,13 @@  static int snd_pioneer_djm_controls_info(struct snd_kcontrol *kctl, struct snd_c
 	return 0;
 }
 
-static int snd_pioneer_djm_controls_update(struct usb_mixer_interface *mixer, u16 group, u16 value)
+static int snd_pioneer_djm_controls_update(struct usb_mixer_interface *mixer,
+		u8 device_idx, u8 group, u16 value)
 {
 	int err;
+	const struct snd_pioneer_djm_device device = snd_pioneer_djm_devices[device_idx];
 
-	if (group >= ARRAY_SIZE(snd_pioneer_djm_option_groups)
-			|| value >= snd_pioneer_djm_option_groups[group].count)
+	if ((group >= device.ncontrols) || value >= device.controls[group].count)
 		return -EINVAL;
 
 	err = snd_usb_lock_shutdown(mixer->chip);
@@ -2747,9 +2833,8 @@  static int snd_pioneer_djm_controls_update(struct usb_mixer_interface *mixer, u1
 	err = snd_usb_ctl_msg(
 		mixer->chip->dev, usb_sndctrlpipe(mixer->chip->dev, 0),
 		USB_REQ_SET_FEATURE,
-		USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
-		snd_pioneer_djm_option_groups[group].options[value].wValue,
-		snd_pioneer_djm_option_groups[group].options[value].wIndex,
+		USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE, device.controls[group].options[value].wValue,
+		device.controls[group].options[value].wIndex,
 		NULL, 0);
 
 	snd_usb_unlock_shutdown(mixer->chip);
@@ -2767,27 +2852,34 @@  static int snd_pioneer_djm_controls_put(struct snd_kcontrol *kctl, struct snd_ct
 	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
 	struct usb_mixer_interface *mixer = list->mixer;
 	unsigned long private_value = kctl->private_value;
-	u16 group = (private_value & SND_PIONEER_DJM_GROUP_MASK) >> SND_PIONEER_DJM_GROUP_SHIFT;
+
+	u8 device = (private_value & SND_PIONEER_DJM_DEVICE_MASK) >> SND_PIONEER_DJM_DEVICE_SHIFT;
+	u8 group = (private_value & SND_PIONEER_DJM_GROUP_MASK) >> SND_PIONEER_DJM_GROUP_SHIFT;
 	u16 value = elem->value.enumerated.item[0];
 
-	kctl->private_value = (group << SND_PIONEER_DJM_GROUP_SHIFT) | value;
+	kctl->private_value = ((device << SND_PIONEER_DJM_DEVICE_SHIFT) |
+			      (group << SND_PIONEER_DJM_GROUP_SHIFT) |
+			      value);
 
-	return snd_pioneer_djm_controls_update(mixer, group, value);
+	return snd_pioneer_djm_controls_update(mixer, device, group, value);
 }
 
 static int snd_pioneer_djm_controls_resume(struct usb_mixer_elem_list *list)
 {
 	unsigned long private_value = list->kctl->private_value;
-	u16 group = (private_value & SND_PIONEER_DJM_GROUP_MASK) >> SND_PIONEER_DJM_GROUP_SHIFT;
+	u8 device = (private_value & SND_PIONEER_DJM_DEVICE_MASK) >> SND_PIONEER_DJM_DEVICE_SHIFT;
+	u8 group = (private_value & SND_PIONEER_DJM_GROUP_MASK) >> SND_PIONEER_DJM_GROUP_SHIFT;
 	u16 value = (private_value & SND_PIONEER_DJM_VALUE_MASK);
-
-	return snd_pioneer_djm_controls_update(list->mixer, group, value);
+	return snd_pioneer_djm_controls_update(list->mixer, device, group, value);
 }
 
-static int snd_pioneer_djm_controls_create(struct usb_mixer_interface *mixer)
+static int snd_pioneer_djm_controls_create(struct usb_mixer_interface *mixer,
+		const u8 device_idx)
 {
 	int err, i;
-	const struct snd_pioneer_djm_option_group *group;
+
+	const struct snd_pioneer_djm_device device = snd_pioneer_djm_devices[device_idx];
+
 	struct snd_kcontrol_new knew = {
 		.iface  = SNDRV_CTL_ELEM_IFACE_MIXER,
 		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE,
@@ -2797,11 +2889,17 @@  static int snd_pioneer_djm_controls_create(struct usb_mixer_interface *mixer)
 		.put  = snd_pioneer_djm_controls_put
 	};
 
-	for (i = 0; i < ARRAY_SIZE(snd_pioneer_djm_option_groups); i++) {
-		group = &snd_pioneer_djm_option_groups[i];
-		knew.name = group->name;
-		knew.private_value = (i << SND_PIONEER_DJM_GROUP_SHIFT) | group->default_value;
-		err = snd_pioneer_djm_controls_update(mixer, i, group->default_value);
+	u16 value;
+	for (i = 0; i < device.ncontrols; i++) {
+		value = device.controls[i].default_value;
+
+		knew.name = device.controls[i].name;
+		knew.private_value = (
+			(device_idx << SND_PIONEER_DJM_DEVICE_SHIFT) |
+			(i << SND_PIONEER_DJM_GROUP_SHIFT) |
+			value);
+
+		err = snd_pioneer_djm_controls_update(mixer, device_idx, i, value);
 		if (err)
 			return err;
 		err = add_single_ctl_with_resume(mixer, 0, snd_pioneer_djm_controls_resume,
@@ -2917,7 +3015,10 @@  int snd_usb_mixer_apply_create_quirk(struct usb_mixer_interface *mixer)
 		err = snd_bbfpro_controls_create(mixer);
 		break;
 	case USB_ID(0x2b73, 0x0017): /* Pioneer DJ DJM-250MK2 */
-		err = snd_pioneer_djm_controls_create(mixer);
+		err = snd_pioneer_djm_controls_create(mixer, 0x00);
+		break;
+	case USB_ID(0x08e4, 0x017f): /* Pioneer DJ DJM-750 */
+		err = snd_pioneer_djm_controls_create(mixer, 0x01);
 		break;
 	}