[ALSA] usb-audio: simplify MIDI quirk handling

Modules: USB generic driver

Simplify the handling of MIDI quirks by treating an interface without
quirks as a QUIRK_MIDI_STANDARD_INTERFACE.

This also fixes the bug where a MIDI_STANDARD quirk would not be
recognized.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

sound/usb/usbaudio.c

@@ -2755,7 +2755,7 @@ static int create_fixed_stream_quirk(snd_usb_audio_t *chip,
 /*
  * create a stream for an interface with proper descriptors
  */
-static int create_standard_interface_quirk(snd_usb_audio_t *chip,
+static int create_standard_audio_quirk(snd_usb_audio_t *chip,
 				       struct usb_interface *iface,
 				       const snd_usb_audio_quirk_t *quirk)
 {
@@ -2765,24 +2765,14 @@ static int create_standard_interface_quirk(snd_usb_audio_t *chip,
 
 	alts = &iface->altsetting[0];
 	altsd = get_iface_desc(alts);
-	switch (quirk->type) {
-	case QUIRK_AUDIO_STANDARD_INTERFACE:
 	err = parse_audio_endpoints(chip, altsd->bInterfaceNumber);
-		if (!err)
-			usb_set_interface(chip->dev, altsd->bInterfaceNumber, 0); /* reset the current interface */
-		break;
-	case QUIRK_MIDI_STANDARD_INTERFACE:
-		err = snd_usb_create_midi_interface(chip, iface, NULL);
-		break;
-	default:
-		snd_printd(KERN_ERR "invalid quirk type %d\n", quirk->type);
-		return -ENXIO;
-	}
 	if (err < 0) {
 		snd_printk(KERN_ERR "cannot setup if %d: error %d\n",
 			   altsd->bInterfaceNumber, err);
 		return err;
 	}
+	/* reset the current interface */
+	usb_set_interface(chip->dev, altsd->bInterfaceNumber, 0);
 	return 0;
 }
 
@@ -3044,7 +3034,7 @@ static int snd_usb_create_quirk(snd_usb_audio_t *chip,
 		[QUIRK_MIDI_RAW] = snd_usb_create_midi_interface,
 		[QUIRK_MIDI_EMAGIC] = snd_usb_create_midi_interface,
 		[QUIRK_MIDI_MIDITECH] = snd_usb_create_midi_interface,
-		[QUIRK_AUDIO_STANDARD_INTERFACE] = create_standard_interface_quirk,
+		[QUIRK_AUDIO_STANDARD_INTERFACE] = create_standard_audio_quirk,
 		[QUIRK_AUDIO_FIXED_ENDPOINT] = create_fixed_stream_quirk,
 		[QUIRK_AUDIO_EDIROL_UA700_UA25] = create_ua700_ua25_quirk,
 		[QUIRK_AUDIO_EDIROL_UA1000] = create_ua1000_quirk,

sound/usb/usbmidi.c

@@ -1550,10 +1550,10 @@ int snd_usb_create_midi_interface(snd_usb_audio_t* chip,
 
 	/* detect the endpoint(s) to use */
 	memset(endpoints, 0, sizeof(endpoints));
-	if (!quirk) {
+	switch (quirk ? quirk->type : QUIRK_MIDI_STANDARD_INTERFACE) {
+	case QUIRK_MIDI_STANDARD_INTERFACE:
 		err = snd_usbmidi_get_ms_info(umidi, endpoints);
-	} else {
-		switch (quirk->type) {
+		break;
 	case QUIRK_MIDI_FIXED_ENDPOINT:
 		memcpy(&endpoints[0], quirk->data,
 		       sizeof(snd_usb_midi_endpoint_info_t));
@@ -1590,7 +1590,6 @@ int snd_usb_create_midi_interface(snd_usb_audio_t* chip,
 		err = -ENXIO;
 		break;
 	}
-	}
 	if (err < 0) {
 		kfree(umidi);
 		return err;