[PATCH 0/5] USB Audio Gadget part 1: misc fixes and improvements

[PATCH 0/5] USB Audio Gadget part 1: misc fixes and improvements

[Ruslan Bilovol]

Here are some bug fixes and improvements to
USB Audio Gadget drivers which I made during
my work on a new UAC features like feedback endpoint
implementation and Volume/Mute controls.

The new UAC features will be sent as a separate
patch set (aka 'part 2') on top of these changes
later this week

Ruslan Bilovol (5):
  usb: gadget: f_uac2: always increase endpoint max_packet_size by one
    audio slot
  usb: gadget: f_uac1: stop playback on function disable
  usb: gadget: f_uac2: validate input parameters
  usb: gadget: f_uac1: validate input parameters
  usb: gadget: f_uac1: disable IN/OUT ep if unused

 drivers/usb/gadget/function/f_uac1.c | 273 ++++++++++++++++++++++++++---------
 drivers/usb/gadget/function/f_uac2.c |  42 +++++-
 2 files changed, 246 insertions(+), 69 deletions(-)

-- 
1.9.1

[PATCH 1/5] usb: gadget: f_uac2: always increase endpoint max_packet_size by one audio slot

[Ruslan Bilovol]

As per UAC2 Audio Data Formats spec (2.3.1.1 USB Packets),
if the sampling rate is a constant, the allowable variation
of number of audio slots per virtual frame is +/- 1 audio slot.

It means that endpoint should be able to accept/send +1 audio
slot.

Previous endpoint max_packet_size calculation code
was adding sometimes +1 audio slot due to DIV_ROUND_UP
behaviour which was rounding up to closest integer.
However this doesn't work if the numbers are divisible.

It had no any impact with Linux hosts which ignore
this issue, but in case of more strict Windows it
caused rejected enumeration

Thus always add +1 audio slot to endpoint's max packet size

Fixes: 913e4a90b6f9 ("usb: gadget: f_uac2: finalize wMaxPacketSize according to bandwidth")
Cc: Peter Chen <peter.chen@freescale.com>
Cc: <stable@vger.kernel.org> #v4.3+
Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
---
 drivers/usb/gadget/function/f_uac2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
index 740cb64..c62cccb 100644
--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -478,7 +478,7 @@ static int set_ep_max_packet_size(const struct f_uac2_opts *uac2_opts,
 	}
 
 	max_size_bw = num_channels(chmask) * ssize *
-		DIV_ROUND_UP(srate, factor / (1 << (ep_desc->bInterval - 1)));
+		((srate / (factor / (1 << (ep_desc->bInterval - 1)))) + 1);
 	ep_desc->wMaxPacketSize = cpu_to_le16(min_t(u16, max_size_bw,
 						    max_size_ep));
 
-- 
1.9.1

[PATCH 2/5] usb: gadget: f_uac1: stop playback on function disable

[Ruslan Bilovol]

There is missing playback stop/cleanup in case of
gadget's ->disable callback that happens on
events like USB host resetting or gadget disconnection

Fixes: 0591bc236015 ("usb: gadget: add f_uac1 variant based on a new u_audio api")

Cc: <stable@vger.kernel.org> # 4.13+
Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
---
 drivers/usb/gadget/function/f_uac1.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/gadget/function/f_uac1.c b/drivers/usb/gadget/function/f_uac1.c
index 00d3469..560382e 100644
--- a/drivers/usb/gadget/function/f_uac1.c
+++ b/drivers/usb/gadget/function/f_uac1.c
@@ -499,6 +499,7 @@ static void f_audio_disable(struct usb_function *f)
 	uac1->as_out_alt = 0;
 	uac1->as_in_alt = 0;
 
+	u_audio_stop_playback(&uac1->g_audio);
 	u_audio_stop_capture(&uac1->g_audio);
 }
 
-- 
1.9.1

[PATCH 3/5] usb: gadget: f_uac2: validate input parameters

[Ruslan Bilovol]

Currently user can configure UAC2 function with
parameters that violate UAC2 spec or are not supported
by UAC2 gadget implementation.

This can lead to incorrect behavior if such gadget
is connected to the host - like enumeration failure
or other issues depending on host's UAC2 driver
implementation, bringing user to a long hours
of debugging the issue.

Instead of silently accept these parameters, throw
an error if they are not valid.

Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
---
 drivers/usb/gadget/function/f_uac2.c | 40 ++++++++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
index c62cccb..d0e50fc 100644
--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -14,6 +14,9 @@
 #include "u_audio.h"
 #include "u_uac2.h"
 
+/* UAC2 spec: 4.1 Audio Channel Cluster Descriptor */
+#define UAC2_CHANNEL_MASK 0x07FFFFFF
+
 /*
  * The driver implements a simple UAC_2 topology.
  * USB-OUT -> IT_1 -> OT_3 -> ALSA_Capture
@@ -604,6 +607,37 @@ static void setup_descriptor(struct f_uac2_opts *opts)
 	hs_audio_desc[i] = NULL;
 }
 
+static int afunc_validate_opts(struct g_audio *agdev)
+{
+	struct f_uac2_opts *opts = g_audio_to_uac2_opts(agdev);
+	struct device *dev = &agdev->gadget->dev;
+
+	if (!opts->p_chmask && !opts->c_chmask) {
+		dev_err(dev, "Error: no playback and capture channels\n");
+		return -EINVAL;
+	} else if (opts->p_chmask & ~UAC2_CHANNEL_MASK) {
+		dev_err(dev, "Error: unsupported playback channels mask\n");
+		return -EINVAL;
+	} else if (opts->c_chmask & ~UAC2_CHANNEL_MASK) {
+		dev_err(dev, "Error: unsupported capture channels mask\n");
+		return -EINVAL;
+	} else if ((opts->p_ssize < 1) || (opts->p_ssize > 4)) {
+		dev_err(dev, "Error: incorrect playback sample size\n");
+		return -EINVAL;
+	} else if ((opts->c_ssize < 1) || (opts->c_ssize > 4)) {
+		dev_err(dev, "Error: incorrect capture sample size\n");
+		return -EINVAL;
+	} else if (!opts->p_srate) {
+		dev_err(dev, "Error: incorrect playback sampling rate\n");
+		return -EINVAL;
+	} else if (!opts->c_srate) {
+		dev_err(dev, "Error: incorrect capture sampling rate\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int
 afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
 {
@@ -612,11 +646,13 @@ static void setup_descriptor(struct f_uac2_opts *opts)
 	struct usb_composite_dev *cdev = cfg->cdev;
 	struct usb_gadget *gadget = cdev->gadget;
 	struct device *dev = &gadget->dev;
-	struct f_uac2_opts *uac2_opts;
+	struct f_uac2_opts *uac2_opts = g_audio_to_uac2_opts(agdev);
 	struct usb_string *us;
 	int ret;
 
-	uac2_opts = container_of(fn->fi, struct f_uac2_opts, func_inst);
+	ret = afunc_validate_opts(agdev);
+	if (ret)
+		return ret;
 
 	us = usb_gstrings_attach(cdev, fn_strings, ARRAY_SIZE(strings_fn));
 	if (IS_ERR(us))
-- 
1.9.1

[PATCH 4/5] usb: gadget: f_uac1: validate input parameters

[Ruslan Bilovol]

Currently user can configure UAC1 function with
parameters that violate UAC1 spec or are not supported
by UAC1 gadget implementation.

This can lead to incorrect behavior if such gadget
is connected to the host - like enumeration failure
or other issues depending on host's UAC1 driver
implementation, bringing user to a long hours
of debugging the issue.

Instead of silently accept these parameters, throw
an error if they are not valid.

Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
---
 drivers/usb/gadget/function/f_uac1.c | 43 ++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/drivers/usb/gadget/function/f_uac1.c b/drivers/usb/gadget/function/f_uac1.c
index 560382e..cce9478f 100644
--- a/drivers/usb/gadget/function/f_uac1.c
+++ b/drivers/usb/gadget/function/f_uac1.c
@@ -19,6 +19,9 @@
 #include "u_audio.h"
 #include "u_uac1.h"
 
+/* UAC1 spec: 3.7.2.3 Audio Channel Cluster Format */
+#define UAC1_CHANNEL_MASK 0x0FFF
+
 struct f_uac1 {
 	struct g_audio g_audio;
 	u8 ac_intf, as_in_intf, as_out_intf;
@@ -30,6 +33,11 @@ static inline struct f_uac1 *func_to_uac1(struct usb_function *f)
 	return container_of(f, struct f_uac1, g_audio.func);
 }
 
+static inline struct f_uac1_opts *g_audio_to_uac1_opts(struct g_audio *audio)
+{
+	return container_of(audio->func.fi, struct f_uac1_opts, func_inst);
+}
+
 /*
  * DESCRIPTORS ... most are static, but strings and full
  * configuration descriptors are built on demand.
@@ -505,6 +513,37 @@ static void f_audio_disable(struct usb_function *f)
 
 /*-------------------------------------------------------------------------*/
 
+static int f_audio_validate_opts(struct g_audio *audio)
+{
+	struct f_uac1_opts *opts = g_audio_to_uac1_opts(audio);
+	struct device *dev = &audio->gadget->dev;
+
+	if (!opts->p_chmask && !opts->c_chmask) {
+		dev_err(dev, "Error: no playback and capture channels\n");
+		return -EINVAL;
+	} else if (opts->p_chmask & ~UAC1_CHANNEL_MASK) {
+		dev_err(dev, "Error: unsupported playback channels mask\n");
+		return -EINVAL;
+	} else if (opts->c_chmask & ~UAC1_CHANNEL_MASK) {
+		dev_err(dev, "Error: unsupported capture channels mask\n");
+		return -EINVAL;
+	} else if ((opts->p_ssize < 1) || (opts->p_ssize > 4)) {
+		dev_err(dev, "Error: incorrect playback sample size\n");
+		return -EINVAL;
+	} else if ((opts->c_ssize < 1) || (opts->c_ssize > 4)) {
+		dev_err(dev, "Error: incorrect capture sample size\n");
+		return -EINVAL;
+	} else if (!opts->p_srate) {
+		dev_err(dev, "Error: incorrect playback sampling rate\n");
+		return -EINVAL;
+	} else if (!opts->c_srate) {
+		dev_err(dev, "Error: incorrect capture sampling rate\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 /* audio function driver setup/binding */
 static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
 {
@@ -519,6 +558,10 @@ static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
 	int				rate;
 	int				status;
 
+	status = f_audio_validate_opts(audio);
+	if (status)
+		return status;
+
 	audio_opts = container_of(f->fi, struct f_uac1_opts, func_inst);
 
 	us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
-- 
1.9.1

[PATCH 5/5] usb: gadget: f_uac1: disable IN/OUT ep if unused

[Ruslan Bilovol]

User can configure f_uac1 function via p_chmask/c_chmask
whether uac1 shall support playback and/or capture,
but it has only effect on the created ALSA device,
but not on the USB descriptor.

This patch adds playback/capture descriptors
dependent on that parameter. It is similar to
the same conversion done earlier for f_uac2

Signed-off-by: Ruslan Bilovol <ruslan.bilovol@gmail.com>
---
 drivers/usb/gadget/function/f_uac1.c | 229 +++++++++++++++++++++++++----------
 1 file changed, 163 insertions(+), 66 deletions(-)

diff --git a/drivers/usb/gadget/function/f_uac1.c b/drivers/usb/gadget/function/f_uac1.c
index cce9478f..b535407 100644
--- a/drivers/usb/gadget/function/f_uac1.c
+++ b/drivers/usb/gadget/function/f_uac1.c
@@ -22,6 +22,9 @@
 /* UAC1 spec: 3.7.2.3 Audio Channel Cluster Format */
 #define UAC1_CHANNEL_MASK 0x0FFF
 
+#define EPIN_EN(_opts) ((_opts)->p_chmask != 0)
+#define EPOUT_EN(_opts) ((_opts)->c_chmask != 0)
+
 struct f_uac1 {
 	struct g_audio g_audio;
 	u8 ac_intf, as_in_intf, as_out_intf;
@@ -50,11 +53,6 @@ static inline struct f_uac1_opts *g_audio_to_uac1_opts(struct g_audio *audio)
  * USB-OUT -> IT_1 -> OT_2 -> ALSA_Capture
  * ALSA_Playback -> IT_3 -> OT_4 -> USB-IN
  */
-#define F_AUDIO_AC_INTERFACE		0
-#define F_AUDIO_AS_OUT_INTERFACE	1
-#define F_AUDIO_AS_IN_INTERFACE		2
-/* Number of streaming interfaces */
-#define F_AUDIO_NUM_INTERFACES		2
 
 /* B.3.1  Standard AC Interface Descriptor */
 static struct usb_interface_descriptor ac_interface_desc = {
@@ -65,73 +63,47 @@ static inline struct f_uac1_opts *g_audio_to_uac1_opts(struct g_audio *audio)
 	.bInterfaceSubClass =	USB_SUBCLASS_AUDIOCONTROL,
 };
 
-/*
- * The number of AudioStreaming and MIDIStreaming interfaces
- * in the Audio Interface Collection
- */
-DECLARE_UAC_AC_HEADER_DESCRIPTOR(2);
-
-#define UAC_DT_AC_HEADER_LENGTH	UAC_DT_AC_HEADER_SIZE(F_AUDIO_NUM_INTERFACES)
-/* 2 input terminals and 2 output terminals */
-#define UAC_DT_TOTAL_LENGTH (UAC_DT_AC_HEADER_LENGTH \
-	+ 2*UAC_DT_INPUT_TERMINAL_SIZE + 2*UAC_DT_OUTPUT_TERMINAL_SIZE)
 /* B.3.2  Class-Specific AC Interface Descriptor */
-static struct uac1_ac_header_descriptor_2 ac_header_desc = {
-	.bLength =		UAC_DT_AC_HEADER_LENGTH,
-	.bDescriptorType =	USB_DT_CS_INTERFACE,
-	.bDescriptorSubtype =	UAC_HEADER,
-	.bcdADC =		cpu_to_le16(0x0100),
-	.wTotalLength =		cpu_to_le16(UAC_DT_TOTAL_LENGTH),
-	.bInCollection =	F_AUDIO_NUM_INTERFACES,
-	.baInterfaceNr = {
-	/* Interface number of the AudioStream interfaces */
-		[0] =		1,
-		[1] =		2,
-	}
-};
+static struct uac1_ac_header_descriptor *ac_header_desc;
 
-#define USB_OUT_IT_ID	1
 static struct uac_input_terminal_descriptor usb_out_it_desc = {
 	.bLength =		UAC_DT_INPUT_TERMINAL_SIZE,
 	.bDescriptorType =	USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype =	UAC_INPUT_TERMINAL,
-	.bTerminalID =		USB_OUT_IT_ID,
+	/* .bTerminalID =	DYNAMIC */
 	.wTerminalType =	cpu_to_le16(UAC_TERMINAL_STREAMING),
 	.bAssocTerminal =	0,
 	.wChannelConfig =	cpu_to_le16(0x3),
 };
 
-#define IO_OUT_OT_ID	2
 static struct uac1_output_terminal_descriptor io_out_ot_desc = {
 	.bLength		= UAC_DT_OUTPUT_TERMINAL_SIZE,
 	.bDescriptorType	= USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype	= UAC_OUTPUT_TERMINAL,
-	.bTerminalID		= IO_OUT_OT_ID,
+	/* .bTerminalID =	DYNAMIC */
 	.wTerminalType		= cpu_to_le16(UAC_OUTPUT_TERMINAL_SPEAKER),
 	.bAssocTerminal		= 0,
-	.bSourceID		= USB_OUT_IT_ID,
+	/* .bSourceID =		DYNAMIC */
 };
 
-#define IO_IN_IT_ID	3
 static struct uac_input_terminal_descriptor io_in_it_desc = {
 	.bLength		= UAC_DT_INPUT_TERMINAL_SIZE,
 	.bDescriptorType	= USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype	= UAC_INPUT_TERMINAL,
-	.bTerminalID		= IO_IN_IT_ID,
+	/* .bTerminalID		= DYNAMIC */
 	.wTerminalType		= cpu_to_le16(UAC_INPUT_TERMINAL_MICROPHONE),
 	.bAssocTerminal		= 0,
 	.wChannelConfig		= cpu_to_le16(0x3),
 };
 
-#define USB_IN_OT_ID	4
 static struct uac1_output_terminal_descriptor usb_in_ot_desc = {
 	.bLength =		UAC_DT_OUTPUT_TERMINAL_SIZE,
 	.bDescriptorType =	USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype =	UAC_OUTPUT_TERMINAL,
-	.bTerminalID =		USB_IN_OT_ID,
+	/* .bTerminalID =	DYNAMIC */
 	.wTerminalType =	cpu_to_le16(UAC_TERMINAL_STREAMING),
 	.bAssocTerminal =	0,
-	.bSourceID =		IO_IN_IT_ID,
+	/* .bSourceID =		DYNAMIC */
 };
 
 /* B.4.1  Standard AS Interface Descriptor */
@@ -176,7 +148,7 @@ static inline struct f_uac1_opts *g_audio_to_uac1_opts(struct g_audio *audio)
 	.bLength =		UAC_DT_AS_HEADER_SIZE,
 	.bDescriptorType =	USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype =	UAC_AS_GENERAL,
-	.bTerminalLink =	USB_OUT_IT_ID,
+	/* .bTerminalLink =	DYNAMIC */
 	.bDelay =		1,
 	.wFormatTag =		cpu_to_le16(UAC_FORMAT_TYPE_I_PCM),
 };
@@ -185,7 +157,7 @@ static inline struct f_uac1_opts *g_audio_to_uac1_opts(struct g_audio *audio)
 	.bLength =		UAC_DT_AS_HEADER_SIZE,
 	.bDescriptorType =	USB_DT_CS_INTERFACE,
 	.bDescriptorSubtype =	UAC_AS_GENERAL,
-	.bTerminalLink =	USB_IN_OT_ID,
+	/* .bTerminalLink =	DYNAMIC */
 	.bDelay =		1,
 	.wFormatTag =		cpu_to_le16(UAC_FORMAT_TYPE_I_PCM),
 };
@@ -513,6 +485,108 @@ static void f_audio_disable(struct usb_function *f)
 
 /*-------------------------------------------------------------------------*/
 
+static struct
+uac1_ac_header_descriptor *build_ac_header_desc(struct f_uac1_opts *opts)
+{
+	struct uac1_ac_header_descriptor *ac_desc;
+	int ac_header_desc_size;
+	int num_ifaces = 0;
+
+	if (EPOUT_EN(opts))
+		num_ifaces++;
+	if (EPIN_EN(opts))
+		num_ifaces++;
+
+	ac_header_desc_size = UAC_DT_AC_HEADER_SIZE(num_ifaces);
+
+	ac_desc = kzalloc(ac_header_desc_size, GFP_KERNEL);
+	if (!ac_desc)
+		return NULL;
+
+	ac_desc->bLength = ac_header_desc_size;
+	ac_desc->bDescriptorType = USB_DT_CS_INTERFACE;
+	ac_desc->bDescriptorSubtype = UAC_HEADER;
+	ac_desc->bcdADC = cpu_to_le16(0x0100);
+	ac_desc->bInCollection = num_ifaces;
+
+	/* wTotalLength and baInterfaceNr will be defined later */
+
+	return ac_desc;
+}
+
+/* Use macro to overcome line length limitation */
+#define USBDHDR(p) (struct usb_descriptor_header *)(p)
+
+static void setup_descriptor(struct f_uac1_opts *opts)
+{
+	/* patch descriptors */
+	int i = 1; /* ID's start with 1 */
+
+	if (EPOUT_EN(opts))
+		usb_out_it_desc.bTerminalID = i++;
+	if (EPIN_EN(opts))
+		io_in_it_desc.bTerminalID = i++;
+	if (EPOUT_EN(opts))
+		io_out_ot_desc.bTerminalID = i++;
+	if (EPIN_EN(opts))
+		usb_in_ot_desc.bTerminalID = i++;
+
+	usb_in_ot_desc.bSourceID = io_in_it_desc.bTerminalID;
+	io_out_ot_desc.bSourceID = usb_out_it_desc.bTerminalID;
+
+	as_out_header_desc.bTerminalLink = usb_out_it_desc.bTerminalID;
+	as_in_header_desc.bTerminalLink = usb_in_ot_desc.bTerminalID;
+
+	ac_header_desc->wTotalLength = cpu_to_le16(ac_header_desc->bLength);
+
+	if (EPIN_EN(opts)) {
+		u16 len = le16_to_cpu(ac_header_desc->wTotalLength);
+
+		len += sizeof(usb_in_ot_desc);
+		len += sizeof(io_in_it_desc);
+		ac_header_desc->wTotalLength = cpu_to_le16(len);
+	}
+	if (EPOUT_EN(opts)) {
+		u16 len = le16_to_cpu(ac_header_desc->wTotalLength);
+
+		len += sizeof(usb_out_it_desc);
+		len += sizeof(io_out_ot_desc);
+		ac_header_desc->wTotalLength = cpu_to_le16(len);
+	}
+
+	i = 0;
+	f_audio_desc[i++] = USBDHDR(&ac_interface_desc);
+	f_audio_desc[i++] = USBDHDR(ac_header_desc);
+
+	if (EPOUT_EN(opts)) {
+		f_audio_desc[i++] = USBDHDR(&usb_out_it_desc);
+		f_audio_desc[i++] = USBDHDR(&io_out_ot_desc);
+	}
+
+	if (EPIN_EN(opts)) {
+		f_audio_desc[i++] = USBDHDR(&io_in_it_desc);
+		f_audio_desc[i++] = USBDHDR(&usb_in_ot_desc);
+	}
+
+	if (EPOUT_EN(opts)) {
+		f_audio_desc[i++] = USBDHDR(&as_out_interface_alt_0_desc);
+		f_audio_desc[i++] = USBDHDR(&as_out_interface_alt_1_desc);
+		f_audio_desc[i++] = USBDHDR(&as_out_header_desc);
+		f_audio_desc[i++] = USBDHDR(&as_out_type_i_desc);
+		f_audio_desc[i++] = USBDHDR(&as_out_ep_desc);
+		f_audio_desc[i++] = USBDHDR(&as_iso_out_desc);
+	}
+	if (EPIN_EN(opts)) {
+		f_audio_desc[i++] = USBDHDR(&as_in_interface_alt_0_desc);
+		f_audio_desc[i++] = USBDHDR(&as_in_interface_alt_1_desc);
+		f_audio_desc[i++] = USBDHDR(&as_in_header_desc);
+		f_audio_desc[i++] = USBDHDR(&as_in_type_i_desc);
+		f_audio_desc[i++] = USBDHDR(&as_in_ep_desc);
+		f_audio_desc[i++] = USBDHDR(&as_iso_in_desc);
+	}
+	f_audio_desc[i] = NULL;
+}
+
 static int f_audio_validate_opts(struct g_audio *audio)
 {
 	struct f_uac1_opts *opts = g_audio_to_uac1_opts(audio);
@@ -556,6 +630,7 @@ static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
 	struct usb_string		*us;
 	u8				*sam_freq;
 	int				rate;
+	int				ba_iface_id;
 	int				status;
 
 	status = f_audio_validate_opts(audio);
@@ -567,6 +642,11 @@ static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
 	us = usb_gstrings_attach(cdev, uac1_strings, ARRAY_SIZE(strings_uac1));
 	if (IS_ERR(us))
 		return PTR_ERR(us);
+
+	ac_header_desc = build_ac_header_desc(audio_opts);
+	if (!ac_header_desc)
+		return -ENOMEM;
+
 	ac_interface_desc.iInterface = us[STR_AC_IF].id;
 	usb_out_it_desc.iTerminal = us[STR_USB_OUT_IT].id;
 	usb_out_it_desc.iChannelNames = us[STR_USB_OUT_IT_CH_NAMES].id;
@@ -607,40 +687,52 @@ static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
 	uac1->ac_intf = status;
 	uac1->ac_alt = 0;
 
-	status = usb_interface_id(c, f);
-	if (status < 0)
-		goto fail;
-	as_out_interface_alt_0_desc.bInterfaceNumber = status;
-	as_out_interface_alt_1_desc.bInterfaceNumber = status;
-	ac_header_desc.baInterfaceNr[0] = status;
-	uac1->as_out_intf = status;
-	uac1->as_out_alt = 0;
+	ba_iface_id = 0;
+
+	if (EPOUT_EN(audio_opts)) {
+		status = usb_interface_id(c, f);
+		if (status < 0)
+			goto fail;
+		as_out_interface_alt_0_desc.bInterfaceNumber = status;
+		as_out_interface_alt_1_desc.bInterfaceNumber = status;
+		ac_header_desc->baInterfaceNr[ba_iface_id++] = status;
+		uac1->as_out_intf = status;
+		uac1->as_out_alt = 0;
+	}
 
-	status = usb_interface_id(c, f);
-	if (status < 0)
-		goto fail;
-	as_in_interface_alt_0_desc.bInterfaceNumber = status;
-	as_in_interface_alt_1_desc.bInterfaceNumber = status;
-	ac_header_desc.baInterfaceNr[1] = status;
-	uac1->as_in_intf = status;
-	uac1->as_in_alt = 0;
+	if (EPIN_EN(audio_opts)) {
+		status = usb_interface_id(c, f);
+		if (status < 0)
+			goto fail;
+		as_in_interface_alt_0_desc.bInterfaceNumber = status;
+		as_in_interface_alt_1_desc.bInterfaceNumber = status;
+		ac_header_desc->baInterfaceNr[ba_iface_id++] = status;
+		uac1->as_in_intf = status;
+		uac1->as_in_alt = 0;
+	}
 
 	audio->gadget = gadget;
 
 	status = -ENODEV;
 
 	/* allocate instance-specific endpoints */
-	ep = usb_ep_autoconfig(cdev->gadget, &as_out_ep_desc);
-	if (!ep)
-		goto fail;
-	audio->out_ep = ep;
-	audio->out_ep->desc = &as_out_ep_desc;
+	if (EPOUT_EN(audio_opts)) {
+		ep = usb_ep_autoconfig(cdev->gadget, &as_out_ep_desc);
+		if (!ep)
+			goto fail;
+		audio->out_ep = ep;
+		audio->out_ep->desc = &as_out_ep_desc;
+	}
 
-	ep = usb_ep_autoconfig(cdev->gadget, &as_in_ep_desc);
-	if (!ep)
-		goto fail;
-	audio->in_ep = ep;
-	audio->in_ep->desc = &as_in_ep_desc;
+	if (EPIN_EN(audio_opts)) {
+		ep = usb_ep_autoconfig(cdev->gadget, &as_in_ep_desc);
+		if (!ep)
+			goto fail;
+		audio->in_ep = ep;
+		audio->in_ep->desc = &as_in_ep_desc;
+	}
+
+	setup_descriptor(audio_opts);
 
 	/* copy descriptors, and track endpoint copies */
 	status = usb_assign_descriptors(f, f_audio_desc, f_audio_desc, NULL,
@@ -667,6 +759,8 @@ static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
 err_card_register:
 	usb_free_all_descriptors(f);
 fail:
+	kfree(ac_header_desc);
+	ac_header_desc = NULL;
 	return status;
 }
 
@@ -809,6 +903,9 @@ static void f_audio_unbind(struct usb_configuration *c, struct usb_function *f)
 	g_audio_cleanup(audio);
 	usb_free_all_descriptors(f);
 
+	kfree(ac_header_desc);
+	ac_header_desc = NULL;
+
 	audio->gadget = NULL;
 }
 
-- 
1.9.1