ALSA: usb-audio - Add ignore_ctl_error parameter

Added the ignore_ctl_error parameter to enable/disable the control-error
handling for mixer interfaces.  It was a hard-coded ifdef, and now you
can change it more easily.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c
index c91f18c..c5cf682 100644
--- a/sound/usb/usbaudio.c
+++ b/sound/usb/usbaudio.c
@@ -71,6 +71,7 @@
 static int nrpacks = 8;		/* max. number of packets per urb */
 static int async_unlink = 1;
 static int device_setup[SNDRV_CARDS]; /* device parameter for this card*/
+static int ignore_ctl_error;
 
 module_param_array(index, int, NULL, 0444);
 MODULE_PARM_DESC(index, "Index value for the USB audio adapter.");
@@ -88,7 +89,9 @@
 MODULE_PARM_DESC(async_unlink, "Use async unlink mode.");
 module_param_array(device_setup, int, NULL, 0444);
 MODULE_PARM_DESC(device_setup, "Specific device setup (if needed).");
-
+module_param(ignore_ctl_error, bool, 0444);
+MODULE_PARM_DESC(ignore_ctl_error,
+		 "Ignore errors from USB controller for mixer interfaces.");
 
 /*
  * debug the h/w constraints
@@ -3633,7 +3636,7 @@
 	if (err > 0) {
 		/* create normal USB audio interfaces */
 		if (snd_usb_create_streams(chip, ifnum) < 0 ||
-		    snd_usb_create_mixer(chip, ifnum) < 0) {
+		    snd_usb_create_mixer(chip, ifnum, ignore_ctl_error) < 0) {
 			goto __error;
 		}
 	}
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index 140ba36..f3ca77f 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -223,7 +223,8 @@
 		    __u8 request, __u8 requesttype, __u16 value, __u16 index,
 		    void *data, __u16 size, int timeout);
 
-int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif);
+int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif,
+			 int ignore_error);
 void snd_usb_mixer_disconnect(struct list_head *p);
 
 int snd_usb_create_midi_interface(struct snd_usb_audio *chip, struct usb_interface *iface,
diff --git a/sound/usb/usbmixer.c b/sound/usb/usbmixer.c
index 6621fad..a492461 100644
--- a/sound/usb/usbmixer.c
+++ b/sound/usb/usbmixer.c
@@ -2014,7 +2014,8 @@
 	}
 }
 
-int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif)
+int snd_usb_create_mixer(struct snd_usb_audio *chip, int ctrlif,
+			 int ignore_error)
 {
 	static struct snd_device_ops dev_ops = {
 		.dev_free = snd_usb_mixer_dev_free
@@ -2029,9 +2030,7 @@
 		return -ENOMEM;
 	mixer->chip = chip;
 	mixer->ctrlif = ctrlif;
-#ifdef IGNORE_CTL_ERROR
-	mixer->ignore_ctl_error = 1;
-#endif
+	mixer->ignore_ctl_error = ignore_error;
 	mixer->id_elems = kcalloc(256, sizeof(*mixer->id_elems), GFP_KERNEL);
 	if (!mixer->id_elems) {
 		kfree(mixer);