diff --git a/src/add-ons/kernel/drivers/audio/hda/Jamfile b/src/add-ons/kernel/drivers/audio/hda/Jamfile
index e735689be8..32995239aa 100644
--- a/src/add-ons/kernel/drivers/audio/hda/Jamfile
+++ b/src/add-ons/kernel/drivers/audio/hda/Jamfile
@@ -5,11 +5,11 @@ SetSubDirSupportedPlatformsBeOSCompatible ;
 UsePrivateHeaders media ;
 
 KernelAddon hda :
-	driver.c
-	hooks.c
-	hda_multi_audio.c
-	hda_controller.c
-	hda_codec.c
+	driver.cpp
+	device.cpp
+	hda_multi_audio.cpp
+	hda_controller.cpp
+	hda_codec.cpp
 ;
 
 Package haiku-hda-cvs :
diff --git a/src/add-ons/kernel/drivers/audio/hda/hooks.c b/src/add-ons/kernel/drivers/audio/hda/device.cpp
similarity index 89%
rename from src/add-ons/kernel/drivers/audio/hda/hooks.c
rename to src/add-ons/kernel/drivers/audio/hda/device.cpp
index c12f7bc5b2..51e3dcebe5 100644
--- a/src/add-ons/kernel/drivers/audio/hda/hooks.c
+++ b/src/add-ons/kernel/drivers/audio/hda/device.cpp
@@ -14,10 +14,8 @@ static status_t
 hda_open(const char *name, uint32 flags, void** cookie)
 {
 	hda_controller* controller = NULL;
-	status_t rc = B_OK;
-	long i;
 
-	for (i = 0; i < gNumCards; i++) {
+	for (uint32 i = 0; i < gNumCards; i++) {
 		if (strcmp(gCards[i].devfs_path, name) == 0) {
 			controller = &gCards[i];
 			break;
@@ -30,11 +28,11 @@ hda_open(const char *name, uint32 flags, void** cookie)
 	if (controller->opened)
 		return B_BUSY;
 
-	rc = hda_hw_init(controller);
-	if (rc != B_OK)
-		return rc;
+	status_t status = hda_hw_init(controller);
+	if (status != B_OK)
+		return status;
 
-	controller->opened++;
+	atomic_add(&controller->opened, 1);
 
 	*cookie = controller;
 	return B_OK;
@@ -75,7 +73,7 @@ hda_close(void* cookie)
 {
 	hda_controller* controller = (hda_controller*)cookie;
 	hda_hw_stop(controller);
-	--controller->opened;
+	atomic_add(&controller->opened, -1);
 
 	return B_OK;
 }
diff --git a/src/add-ons/kernel/drivers/audio/hda/driver.c b/src/add-ons/kernel/drivers/audio/hda/driver.cpp
similarity index 92%
rename from src/add-ons/kernel/drivers/audio/hda/driver.c
rename to src/add-ons/kernel/drivers/audio/hda/driver.cpp
index c65ed8b0b6..a2af84ccee 100644
--- a/src/add-ons/kernel/drivers/audio/hda/driver.c
+++ b/src/add-ons/kernel/drivers/audio/hda/driver.cpp
@@ -17,7 +17,7 @@ uint32 gNumCards;
 pci_module_info* gPci;
 
 
-status_t
+extern "C" status_t
 init_hardware(void)
 {
 	pci_info info;
@@ -39,7 +39,7 @@ init_hardware(void)
 }
 
 
-status_t
+extern "C" status_t
 init_driver(void)
 {
 	char path[B_PATH_NAME_LENGTH];
@@ -76,13 +76,12 @@ init_driver(void)
 }
 
 
-void
+extern "C" void
 uninit_driver(void)
 {
-	long i;
 	dprintf("IRA: %s\n", __func__);
 
-	for (i = 0; i < gNumCards; i++) {
+	for (uint32 i = 0; i < gNumCards; i++) {
 		free((void*)gCards[i].devfs_path);
 		gCards[i].devfs_path = NULL;
 	}
@@ -91,15 +90,16 @@ uninit_driver(void)
 }
 
 
-const char**
+extern "C" const char**
 publish_devices(void)
 {
 	static const char* devs[MAX_CARDS + 1];
-	long i;
+	uint32 i;
 
 	dprintf("IRA: %s\n", __func__);
-	for (i = 0; i < gNumCards; i++)
+	for (i = 0; i < gNumCards; i++) {
 		devs[i] = gCards[i].devfs_path;
+	}
 
 	devs[i] = NULL;
 
@@ -107,7 +107,7 @@ publish_devices(void)
 }
 
 
-device_hooks*
+extern "C" device_hooks*
 find_device(const char* name)
 {
 	dprintf("IRA: %s\n", __func__);
diff --git a/src/add-ons/kernel/drivers/audio/hda/driver.h b/src/add-ons/kernel/drivers/audio/hda/driver.h
index 62f64f4cdc..9768ac2eb8 100644
--- a/src/add-ons/kernel/drivers/audio/hda/driver.h
+++ b/src/add-ons/kernel/drivers/audio/hda/driver.h
@@ -40,10 +40,6 @@
 /* FIXME: Find out why we need so much! */
 #define DEFAULT_FRAMES_PER_BUFFER	4096
 
-typedef struct hda_controller hda_controller;
-typedef struct hda_codec hda_codec;
-typedef struct hda_audio_group hda_audio_group;
-
 #define STREAM_MAX_BUFFERS	10
 #define STREAM_MIN_BUFFERS	2
 
@@ -52,12 +48,12 @@ enum {
 	STREAM_RECORD
 };
 
-/* hda_stream
- *
- * This structure describes a single stream of audio data,
- * which is can have multiple channels (for stereo or better).
- */
-typedef struct hda_stream {
+struct hda_codec;
+
+/*!	This structure describes a single stream of audio data,
+	which is can have multiple channels (for stereo or better).
+*/
+struct hda_stream {
 	uint32		id;					/* HDA controller stream # */
 	uint32		off;				/* HDA I/O/B descriptor offset */
 	bool		running;			/* Is this stream active? */
@@ -74,7 +70,7 @@ typedef struct hda_stream {
 	uint32		num_channels;
 	uint32		buffer_length;		/* size of buffer in samples */
 	uint32		sample_size;
-	void*		buffers[STREAM_MAX_BUFFERS];
+	uint8*		buffers[STREAM_MAX_BUFFERS];
 					/* Virtual addresses for buffer */
 	uint32		physical_buffers[STREAM_MAX_BUFFERS];
 					/* Physical addresses for buffer */
@@ -88,68 +84,66 @@ typedef struct hda_stream {
 	area_id		buffer_area;
 	area_id		buffer_descriptors_area;
 	uint32		physical_buffer_descriptors;	/* BDL physical address */
-} hda_stream;
-
-/* hda_audio_group
- *
- * This structure describes a single Audio Function Group. An afg
- * is a group of audio widgets which can be used to configure multiple
- * streams of audio either from the HDA Link to an output device (= playback)
- * or from an input device to the HDA link (= recording).
- */
-struct hda_audio_group {
-	hda_codec*			codec;
-
-	/* Multi Audio API data */
-	hda_stream*			playback_stream;
-	hda_stream*			record_stream;
-
-	uint32				root_node_id;
-	uint32				widget_start;
-	uint32				widget_count;
-
-	uint32				supported_formats;
-	uint32				supported_rates;
-	uint32				supported_pm;
-
-	struct {
-		uint32			num_inputs;
-		int32			active_input;
-		uint32			inputs[MAX_INPUTS];
-		uint32			flags;
-
-		hda_widget_type	type;
-		uint32			pm;
-
-		union {
-			struct {
-				uint32	formats;
-				uint32	rates;
-			} output;
-			struct {
-				uint32	formats;
-				uint32	rates;
-			} input;
-			struct {
-			} mixer;
-			struct {
-				uint32	output;
-				uint32	input;
-				pin_dev_type device;
-			} pin;
-		} d;
-	} *widgets;
 };
 
-/* hda_codec
- *
- * This structure describes a single codec module in the
- * HDA compliant device. This is a discrete component, which
- * can contain both Audio Function Groups, Modem Function Groups,
- * and other customized (vendor specific) Function Groups.
- *
- * NOTE: Atm, only Audio Function Groups are supported.
- */
+struct hda_widget {
+	uint32			num_inputs;
+	int32			active_input;
+	uint32			inputs[MAX_INPUTS];
+	uint32			flags;
+
+	hda_widget_type	type;
+	uint32			pm;
+
+	union {
+		struct {
+			uint32	formats;
+			uint32	rates;
+		} output;
+		struct {
+			uint32	formats;
+			uint32	rates;
+		} input;
+		struct {
+		} mixer;
+		struct {
+			uint32	output;
+			uint32	input;
+			pin_dev_type device;
+		} pin;
+	} d;
+};
+
+/*!	This structure describes a single Audio Function Group. An afg
+	is a group of audio widgets which can be used to configure multiple
+	streams of audio either from the HDA Link to an output device (= playback)
+	or from an input device to the HDA link (= recording).
+*/
+struct hda_audio_group {
+	hda_codec*		codec;
+
+	/* Multi Audio API data */
+	hda_stream*		playback_stream;
+	hda_stream*		record_stream;
+
+	uint32			root_node_id;
+	uint32			widget_start;
+	uint32			widget_count;
+
+	uint32			supported_formats;
+	uint32			supported_rates;
+	uint32			supported_pm;
+
+	hda_widget*		widgets;
+};
+
+/*!	This structure describes a single codec module in the
+	HDA compliant device. This is a discrete component, which
+	can contain both Audio Function Groups, Modem Function Groups,
+	and other customized (vendor specific) Function Groups.
+
+	NOTE: ATM, only Audio Function Groups are supported.
+*/
 struct hda_codec {
 	uint16		vendor_id;
 	uint16		product_id;
@@ -167,16 +161,14 @@ struct hda_codec {
 	struct hda_controller* controller;
 };
 
-/* hda_controller
- *
- * This structure describes a single HDA compliant 
- * controller. It contains a list of available streams
- * for use by the codecs contained, and the messaging queue
- * (verb/response) buffers for communication.
- */
+/*!	This structure describes a single HDA compliant 
+	controller. It contains a list of available streams
+	for use by the codecs contained, and the messaging queue
+	(verb/response) buffers for communication.
+*/
 struct hda_controller {
 	struct pci_info	pci_info;
-	vuint32			opened;
+	vint32			opened;
 	const char*		devfs_path;
 
 	area_id			regs_area;
@@ -222,7 +214,7 @@ status_t hda_hw_init(hda_controller* controller);
 void hda_hw_stop(hda_controller* controller);
 void hda_hw_uninit(hda_controller* controller);
 status_t hda_send_verbs(hda_codec* codec, corb_t* verbs, uint32* responses,
-	int count);
+	uint32 count);
 
 /* hda_controller.c: Stream support */
 hda_stream* hda_stream_new(hda_controller* controller, int type);
diff --git a/src/add-ons/kernel/drivers/audio/hda/hda_codec.c b/src/add-ons/kernel/drivers/audio/hda/hda_codec.cpp
similarity index 83%
rename from src/add-ons/kernel/drivers/audio/hda/hda_codec.c
rename to src/add-ons/kernel/drivers/audio/hda/hda_codec.cpp
index f31ad97375..15b27c18b2 100644
--- a/src/add-ons/kernel/drivers/audio/hda/hda_codec.c
+++ b/src/add-ons/kernel/drivers/audio/hda/hda_codec.cpp
@@ -174,7 +174,7 @@ hda_codec_parse_audio_group(hda_audio_group* audioGroup)
 	audioGroup->widget_start = resp[2] >> 16;
 	audioGroup->widget_count = resp[2] & 0xFF;
 
-	audioGroup->widgets = calloc(audioGroup->widget_count,
+	audioGroup->widgets = (hda_widget*)calloc(audioGroup->widget_count,
 		sizeof(*audioGroup->widgets));
 	if (audioGroup->widgets == NULL) {
 		dprintf("ERROR: Not enough memory!\n");
@@ -193,7 +193,7 @@ hda_codec_parse_audio_group(hda_audio_group* audioGroup)
 			PID_CONNLIST_LEN);
 		hda_send_verbs(audioGroup->codec, verbs, resp, 2);
 
-		audioGroup->widgets[widx].type = resp[0] >> 20;
+		audioGroup->widgets[widx].type = (hda_widget_type)(resp[0] >> 20);
 		audioGroup->widgets[widx].num_inputs = resp[1] & 0x7F;
 
 		off = 0;
@@ -272,7 +272,8 @@ hda_codec_parse_audio_group(hda_audio_group* audioGroup)
 				verbs[0] = MAKE_VERB(audioGroup->codec->addr, wid,
 					VID_GET_CFGDEFAULT, 0);
 				if (hda_send_verbs(audioGroup->codec, verbs, resp, 1) == B_OK) {
-					audioGroup->widgets[widx].d.pin.device = (resp[0] >> 20) & 0xF;
+					audioGroup->widgets[widx].d.pin.device = (pin_dev_type)
+						((resp[0] >> 20) & 0xf);
 					dprintf("\t%s, %s, %s, %s\n",
 						kPortConnector[resp[0] >> 30],	
 						kDefaultDevice[audioGroup->widgets[widx].d.pin.device],
@@ -304,10 +305,6 @@ hda_codec_parse_audio_group(hda_audio_group* audioGroup)
 			&audioGroup->widgets[widx].pm);
 
 		if (audioGroup->widgets[widx].num_inputs) {
-			int idx;
-
-			off = 0;
-
 			if (audioGroup->widgets[widx].num_inputs > 1) {
 				verbs[0] = MAKE_VERB(audioGroup->codec->addr, wid,
 					VID_GET_CONNSEL, 0);
@@ -318,10 +315,12 @@ hda_codec_parse_audio_group(hda_audio_group* audioGroup)
 			} else 
 				audioGroup->widgets[widx].active_input = -1;
 
-			for (idx = 0; idx < audioGroup->widgets[widx].num_inputs; idx ++) {
-				if (!(idx % 4)) {
+			off = 0;
+
+			for (uint32 i = 0; i < audioGroup->widgets[widx].num_inputs; i++) {
+				if (!(i % 4)) {
 					verbs[0] = MAKE_VERB(audioGroup->codec->addr, wid,
-						VID_GET_CONNLENTRY, idx);
+						VID_GET_CONNLENTRY, i);
 					if (hda_send_verbs(audioGroup->codec, verbs, resp, 1) != B_OK) {
 						dprintf("%s: Error parsing inputs for widget %ld!\n",
 							__func__, wid);
@@ -329,16 +328,16 @@ hda_codec_parse_audio_group(hda_audio_group* audioGroup)
 					}
 				}
 
-				if (idx != audioGroup->widgets[widx].active_input) {
+				if ((int32)i != audioGroup->widgets[widx].active_input) {
 					off += sprintf(buf + off, "%ld ",
-						(resp[0] >> (8 * (idx % 4))) & 0xff);
+						(resp[0] >> (8 * (i % 4))) & 0xff);
 				} else {
 					off += sprintf(buf + off, "(%ld) ",
-						(resp[0] >> (8 * (idx % 4))) & 0xff);
+						(resp[0] >> (8 * (i % 4))) & 0xff);
 				}
 
-				audioGroup->widgets[widx].inputs[idx]
-					= (resp[0] >> (8 * (idx % 4))) & 0xff;
+				audioGroup->widgets[widx].inputs[i]
+					= (resp[0] >> (8 * (i % 4))) & 0xff;
 			}
 
 			dprintf("\t[ %s]\n", buf);
@@ -349,35 +348,35 @@ hda_codec_parse_audio_group(hda_audio_group* audioGroup)
 }
 
 
-/*! Find path from 'wid' to a widget of type 'wtype', returning its widget id.
- * Returns 0 if not found.
- */
+/*! Find path from 'wid' to a widget of type \a widgetType, returning its
+	widget id.
+	Returns 0 if not found.
+*/
 static uint32
 hda_codec_audio_group_find_path(hda_audio_group* audioGroup, uint32 widget,
-	uint32 widgetType, uint32 depth)
+	hda_widget_type widgetType, uint32 depth)
 {
 	int widx = widget - audioGroup->widget_start;
-	int idx;
 
 	switch (audioGroup->widgets[widx].type) {
 		case WT_AUDIO_MIXER:
-			for (idx = 0; idx < audioGroup->widgets[widx].num_inputs; idx++) {
+			for (uint32 i = 0; i < audioGroup->widgets[widx].num_inputs; i++) {
 				if (hda_codec_audio_group_find_path(audioGroup,
-						audioGroup->widgets[widx].inputs[idx], widgetType,
+						audioGroup->widgets[widx].inputs[i], widgetType,
 						depth + 1)) {
 					if (audioGroup->widgets[widx].active_input == -1)
-						audioGroup->widgets[widx].active_input = idx;
+						audioGroup->widgets[widx].active_input = i;
 
-					return audioGroup->widgets[widx].inputs[idx];
+					return audioGroup->widgets[widx].inputs[i];
 				}
 			}
 			break;
 
 		case WT_AUDIO_SELECTOR:
 		{
-			int idx = audioGroup->widgets[widx].active_input;
-			if (idx != -1) {
-				widget = audioGroup->widgets[widx].inputs[idx];
+			int32 i = audioGroup->widgets[widx].active_input;
+			if (i != -1) {
+				widget = audioGroup->widgets[widx].inputs[i];
 				if (hda_codec_audio_group_find_path(audioGroup, widget,
 						widgetType, depth + 1)) {
 					return widget;
@@ -417,49 +416,48 @@ hda_codec_delete_audio_group(hda_audio_group* audioGroup)
 static status_t
 hda_codec_new_audio_group(hda_codec* codec, uint32 audioGroupNodeID)
 {
-	hda_audio_group* audioGroup;
-	status_t rc;
-	uint32 idx;
-
-	if ((audioGroup = calloc(1, sizeof(hda_audio_group))) == NULL) {
-		rc =  B_NO_MEMORY;
-		goto done;
-	}
+	hda_audio_group* audioGroup = (hda_audio_group*)calloc(1,
+		sizeof(hda_audio_group));
+	if (audioGroup == NULL)
+		return B_NO_MEMORY;
 
 	/* Setup minimal info needed by hda_codec_parse_afg */
 	audioGroup->root_node_id = audioGroupNodeID;
 	audioGroup->codec = codec;
 
 	/* Parse all widgets in Audio Function Group */
-	rc = hda_codec_parse_audio_group(audioGroup);
-	if (rc != B_OK)
-		goto free_audio_group;
+	status_t status = hda_codec_parse_audio_group(audioGroup);
+	if (status != B_OK)
+		goto err;
 
 	/* Setup for worst-case scenario; we cannot find any output Pin Widgets */
-	rc = ENODEV;
+	status = ENODEV;
 
 	/* Try to locate all input/output channels */
-	for (idx = 0; idx < audioGroup->widget_count; idx++) {
+	for (uint32 i = 0; i < audioGroup->widget_count; i++) {
 		uint32 outputWidget = 0, inputWidget = 0;
-		int32 iidx;
 
 		if (audioGroup->playback_stream == NULL
-			&& audioGroup->widgets[idx].type == WT_PIN_COMPLEX
-			&& audioGroup->widgets[idx].d.pin.output) {
-			if (audioGroup->widgets[idx].d.pin.device == PIN_DEV_HP_OUT
-				|| audioGroup->widgets[idx].d.pin.device == PIN_DEV_SPEAKER
-				|| audioGroup->widgets[idx].d.pin.device == PIN_DEV_LINE_OUT) {
-				iidx = audioGroup->widgets[idx].active_input;
-				if (iidx != -1) {
+			&& audioGroup->widgets[i].type == WT_PIN_COMPLEX
+			&& audioGroup->widgets[i].d.pin.output) {
+			if (audioGroup->widgets[i].d.pin.device == PIN_DEV_HP_OUT
+				|| audioGroup->widgets[i].d.pin.device == PIN_DEV_SPEAKER
+				|| audioGroup->widgets[i].d.pin.device == PIN_DEV_LINE_OUT) {
+				int32 inputIndex = audioGroup->widgets[i].active_input;
+				if (inputIndex != -1) {
 					outputWidget = hda_codec_audio_group_find_path(audioGroup,
-						audioGroup->widgets[idx].inputs[iidx], WT_AUDIO_OUTPUT, 0);
+						audioGroup->widgets[i].inputs[inputIndex],
+						WT_AUDIO_OUTPUT, 0);
 				} else {
-					for (iidx = 0; iidx < audioGroup->widgets[idx].num_inputs; iidx++) {
+					for (inputIndex = 0; (uint32)inputIndex
+							< audioGroup->widgets[i].num_inputs; inputIndex++) {
 						outputWidget = hda_codec_audio_group_find_path(audioGroup,
-							audioGroup->widgets[idx].inputs[iidx], WT_AUDIO_OUTPUT, 0);
+							audioGroup->widgets[i].inputs[inputIndex],
+							WT_AUDIO_OUTPUT, 0);
 						if (outputWidget) {
 							corb_t verb = MAKE_VERB(codec->addr,
-								idx + audioGroup->widget_start, VID_SET_CONNSEL, iidx);
+								i + audioGroup->widget_start, VID_SET_CONNSEL,
+								inputIndex);
 							if (hda_send_verbs(codec, &verb, NULL, 1) != B_OK)
 								dprintf("%s: Setting output selector failed!\n", __func__);
 							break;
@@ -477,40 +475,45 @@ hda_codec_new_audio_group(hda_codec* codec, uint32 audioGroupNodeID)
 						audioGroup->record_stream = hda_stream_new(
 							audioGroup->codec->controller, STREAM_RECORD);
 
-						audioGroup->playback_stream->pin_widget = idx
+						audioGroup->playback_stream->pin_widget = i
 							+ audioGroup->widget_start;
 						audioGroup->playback_stream->io_widget = outputWidget;
 
 						/* FIXME: Force Pin Widget to unmute; enable hp/output */
 						verb[0] = MAKE_VERB(codec->addr,
-							audioGroup->playback_stream->pin_widget, VID_SET_AMPGAINMUTE,
+							audioGroup->playback_stream->pin_widget,
+							VID_SET_AMPGAINMUTE,
 							(1 << 15) | (1 << 13) | (1 << 12));
 						verb[1] = MAKE_VERB(codec->addr,
-							audioGroup->playback_stream->pin_widget, VID_SET_PINWCTRL,
+							audioGroup->playback_stream->pin_widget,
+							VID_SET_PINWCTRL,
 							(1 << 7) | (1 << 6));
 						hda_send_verbs(codec, verb, NULL, 2);
 
 						dprintf("%s: Found output PIN (%s) connected to output "
 							"CONV wid:%ld\n", __func__,
-							kDefaultDevice[audioGroup->widgets[idx].d.pin.device], outputWidget);
+							kDefaultDevice[audioGroup->widgets[i].d.pin.device], outputWidget);
 					}	
 				}
 			}
 		}
 
-		if (audioGroup->widgets[idx].type == WT_AUDIO_INPUT) {
-			iidx = audioGroup->widgets[idx].active_input;
-			if (iidx != -1) {
+		if (audioGroup->widgets[i].type == WT_AUDIO_INPUT) {
+			int32 inputIndex = audioGroup->widgets[i].active_input;
+			if (inputIndex != -1) {
 				inputWidget = hda_codec_audio_group_find_path(audioGroup,
-					audioGroup->widgets[idx].inputs[iidx], WT_PIN_COMPLEX, 0);
+					audioGroup->widgets[i].inputs[inputIndex], WT_PIN_COMPLEX,
+					0);
 			} else {
-				for (iidx = 0; iidx < audioGroup->widgets[idx].num_inputs; iidx++) {
+				for (inputIndex = 0; (uint32)inputIndex
+						< audioGroup->widgets[i].num_inputs; inputIndex++) {
 					inputWidget = hda_codec_audio_group_find_path(audioGroup,
-						audioGroup->widgets[idx].inputs[iidx], WT_PIN_COMPLEX, 0);
+						audioGroup->widgets[i].inputs[inputIndex],
+						WT_PIN_COMPLEX, 0);
 					if (inputWidget) {
 						corb_t verb = MAKE_VERB(codec->addr,
-							idx + audioGroup->widget_start, VID_SET_CONNSEL,
-							iidx);
+							i + audioGroup->widget_start, VID_SET_CONNSEL,
+							inputIndex);
 						if (hda_send_verbs(codec, &verb, NULL, 1) != B_OK) {
 							dprintf("%s: Setting input selector failed!\n",
 								__func__);
@@ -529,7 +532,7 @@ hda_codec_new_audio_group(hda_codec* codec, uint32 audioGroupNodeID)
 						audioGroup->codec->controller, STREAM_RECORD);
 
 					audioGroup->record_stream->pin_widget = inputWidget;
-					audioGroup->record_stream->io_widget = idx
+					audioGroup->record_stream->io_widget = i
 						+ audioGroup->widget_start;
 
 					/* FIXME: Force Pin Widget to unmute */
@@ -542,7 +545,7 @@ hda_codec_new_audio_group(hda_codec* codec, uint32 audioGroupNodeID)
 				dprintf("%s: Found input PIN (%s) connected to input CONV "
 					"wid:%ld\n", __func__, kDefaultDevice[audioGroup->widgets[
 						inputWidget - audioGroup->widget_start].d.pin.device],
-					idx + audioGroup->widget_start);
+					i + audioGroup->widget_start);
 			}
 		}
 	}
@@ -550,15 +553,12 @@ hda_codec_new_audio_group(hda_codec* codec, uint32 audioGroupNodeID)
 	/* If we found any valid output channels, we're in the clear */
 	if (audioGroup && audioGroup->playback_stream) {
 		codec->audio_groups[codec->num_audio_groups++] = audioGroup;
-		rc = B_OK;
-		goto done;
+		return B_OK;
 	}
 
-free_audio_group:
+err:
 	free(audioGroup);
-
-done:
-	return rc;
+	return status;
 }
 
 
@@ -586,7 +586,7 @@ hda_codec_delete(hda_codec* codec)
 hda_codec*
 hda_codec_new(hda_controller* controller, uint32 cad)
 {
-	hda_codec* codec = calloc(1, sizeof(hda_codec));
+	hda_codec* codec = (hda_codec*)calloc(1, sizeof(hda_codec));
 	uint32 responses[3];
 	corb_t verbs[3];
 	uint32 nodeID;
diff --git a/src/add-ons/kernel/drivers/audio/hda/hda_codec_defs.h b/src/add-ons/kernel/drivers/audio/hda/hda_codec_defs.h
index 2e4f229db7..ce269bd6e3 100644
--- a/src/add-ons/kernel/drivers/audio/hda/hda_codec_defs.h
+++ b/src/add-ons/kernel/drivers/audio/hda/hda_codec_defs.h
@@ -8,7 +8,7 @@
 #ifndef HDA_CODEC_H
 #define HDA_CODEC_H
 
-typedef enum {
+enum hda_widget_type {
 	WT_AUDIO_OUTPUT		= 0,
 	WT_AUDIO_INPUT		= 1,
 	WT_AUDIO_MIXER		= 2,
@@ -18,10 +18,10 @@ typedef enum {
 	WT_VOLUME_KNOB		= 6,
 	WT_BEEP_GENERATOR	= 7,
 	WT_VENDOR_DEFINED	= 15
-} hda_widget_type;
+};
 
 
-typedef enum {
+enum pin_dev_type {
 	PIN_DEV_LINE_OUT = 0,
 	PIN_DEV_SPEAKER,
 	PIN_DEV_HP_OUT,
@@ -38,7 +38,7 @@ typedef enum {
 	PIN_DEV_DIGITAL_OTHER_IN,
 	PIN_DEV_RESERVED,
 	PIN_DEV_OTHER
-} pin_dev_type;
+};
 
 
 /* Verb Helper Macro */
diff --git a/src/add-ons/kernel/drivers/audio/hda/hda_controller.c b/src/add-ons/kernel/drivers/audio/hda/hda_controller.cpp
similarity index 99%
rename from src/add-ons/kernel/drivers/audio/hda/hda_controller.c
rename to src/add-ons/kernel/drivers/audio/hda/hda_controller.cpp
index 76c9510290..07f3a16899 100644
--- a/src/add-ons/kernel/drivers/audio/hda/hda_controller.c
+++ b/src/add-ons/kernel/drivers/audio/hda/hda_controller.cpp
@@ -4,6 +4,7 @@
  *
  * Authors:
  *		Ithamar Adema, ithamar AT unet DOT nl
+ *		Axel Dörfler, axeld@pinc-software.de
  */
 
 
@@ -79,7 +80,7 @@ hda_stream_delete(hda_stream* stream)
 hda_stream*
 hda_stream_new(hda_controller* controller, int type)
 {
-	hda_stream* stream = calloc(1, sizeof(hda_stream));
+	hda_stream* stream = (hda_stream*)calloc(1, sizeof(hda_stream));
 	if (stream == NULL)
 		return NULL;
 
@@ -333,7 +334,7 @@ dprintf("HDA: sample size %ld, num channels %ld, buffer length %ld *************
 
 
 status_t
-hda_send_verbs(hda_codec* codec, corb_t* verbs, uint32* responses, int count)
+hda_send_verbs(hda_codec* codec, corb_t* verbs, uint32* responses, uint32 count)
 {
 	hda_controller *controller = codec->controller;
 	uint32 sent = 0;
@@ -410,7 +411,7 @@ hda_interrupt_handler(hda_controller* controller)
 
 					if ((responseFlags & RESPONSE_FLAGS_UNSOLICITED) != 0) {
 						dprintf("hda: Unsolicited response: %08lx/%08lx\n",
-							response, extendedResponse);
+							response, responseFlags);
 						continue;
 					}
 					if (codec == NULL) {
diff --git a/src/add-ons/kernel/drivers/audio/hda/hda_multi_audio.c b/src/add-ons/kernel/drivers/audio/hda/hda_multi_audio.cpp
similarity index 87%
rename from src/add-ons/kernel/drivers/audio/hda/hda_multi_audio.c
rename to src/add-ons/kernel/drivers/audio/hda/hda_multi_audio.cpp
index f40c82582a..942451030b 100644
--- a/src/add-ons/kernel/drivers/audio/hda/hda_multi_audio.c
+++ b/src/add-ons/kernel/drivers/audio/hda/hda_multi_audio.cpp
@@ -188,11 +188,6 @@ list_mix_channels(hda_audio_group* audioGroup, multi_mix_channel_info *data)
 static status_t
 get_buffers(hda_audio_group* audioGroup, multi_buffer_list* data)
 {
-	uint32 playbackSampleSize = audioGroup->playback_stream->sample_size;
-	uint32 recordSampleSize = audioGroup->record_stream->sample_size;
-	uint32 cidx, bidx;
-	status_t status;
-
 	TRACE("playback: %ld buffers, %ld channels, %ld samples\n",
 		data->request_playback_buffers, data->request_playback_channels,
 		data->request_playback_buffer_size);
@@ -237,8 +232,8 @@ get_buffers(hda_audio_group* audioGroup, multi_buffer_list* data)
 	audioGroup->playback_stream->buffer_length
 		= data->return_playback_buffer_size;
 
-	status = hda_stream_setup_buffers(audioGroup, audioGroup->playback_stream,
-		"Playback");
+	status_t status = hda_stream_setup_buffers(audioGroup,
+		audioGroup->playback_stream, "Playback");
 	if (status != B_OK) {
 		dprintf("hda: Error setting up playback buffers: %s\n",
 			strerror(status));
@@ -260,22 +255,27 @@ get_buffers(hda_audio_group* audioGroup, multi_buffer_list* data)
 
 	/* Setup data structure for multi_audio API... */
 
-	for (bidx = 0; bidx < data->return_playback_buffers; bidx++) {
-		for (cidx = 0; cidx < data->return_playback_channels; cidx++) {
-			data->playback_buffers[bidx][cidx].base
-				= audioGroup->playback_stream->buffers[bidx]
-					+ playbackSampleSize * cidx;
-			data->playback_buffers[bidx][cidx].stride
+	uint32 playbackSampleSize = audioGroup->playback_stream->sample_size;
+	uint32 recordSampleSize = audioGroup->record_stream->sample_size;
+
+	for (int32 i = 0; i < data->return_playback_buffers; i++) {
+		for (int32 channelIndex = 0;
+				channelIndex < data->return_playback_channels; channelIndex++) {
+			data->playback_buffers[i][channelIndex].base
+				= (char*)audioGroup->playback_stream->buffers[i]
+					+ playbackSampleSize * channelIndex;
+			data->playback_buffers[i][channelIndex].stride
 				= playbackSampleSize * data->return_playback_channels;
 		}
 	}
 
-	for (bidx = 0; bidx < data->return_record_buffers; bidx++) {
-		for (cidx = 0; cidx < data->return_record_channels; cidx++) {
-			data->record_buffers[bidx][cidx].base
-				= audioGroup->record_stream->buffers[bidx]
-					+ recordSampleSize * cidx;
-			data->record_buffers[bidx][cidx].stride
+	for (int32 i = 0; i < data->return_record_buffers; i++) {
+		for (int32 channelIndex = 0;
+				channelIndex < data->return_record_channels; channelIndex++) {
+			data->record_buffers[i][channelIndex].base
+				= (char*)audioGroup->record_stream->buffers[i]
+					+ recordSampleSize * channelIndex;
+			data->record_buffers[i][channelIndex].stride
 				= recordSampleSize * data->return_record_channels;
 		}
 	}
@@ -347,31 +347,34 @@ multi_audio_control(void* cookie, uint32 op, void* arg, size_t len)
 
 	audioGroup = codec->audio_groups[0];
 
+	// TODO: make userland-safe when built for Haiku!
+
 	switch (op) {
 		case B_MULTI_GET_DESCRIPTION:
-			return get_description(audioGroup, arg);
+			return get_description(audioGroup, (multi_description*)arg);
 
 		case B_MULTI_GET_ENABLED_CHANNELS:
-			return get_enabled_channels(audioGroup, arg);
+			return get_enabled_channels(audioGroup, (multi_channel_enable*)arg);
 		case B_MULTI_SET_ENABLED_CHANNELS:
 			return B_OK;
 
 		case B_MULTI_GET_GLOBAL_FORMAT:
-			return get_global_format(audioGroup, arg);
+			return get_global_format(audioGroup, (multi_format_info*)arg);
 		case B_MULTI_SET_GLOBAL_FORMAT:
-			return set_global_format(audioGroup, arg);
+			return set_global_format(audioGroup, (multi_format_info*)arg);
 
 		case B_MULTI_LIST_MIX_CHANNELS:
-			return list_mix_channels(audioGroup, arg);
+			return list_mix_channels(audioGroup, (multi_mix_channel_info*)arg);
 		case B_MULTI_LIST_MIX_CONTROLS:
-			return list_mix_controls(audioGroup, arg);
+			return list_mix_controls(audioGroup, (multi_mix_control_info*)arg);
 		case B_MULTI_LIST_MIX_CONNECTIONS:
-			return list_mix_connections(audioGroup, arg);
+			return list_mix_connections(audioGroup,
+				(multi_mix_connection_info*)arg);
 		case B_MULTI_GET_BUFFERS:
-			return get_buffers(audioGroup, arg);
+			return get_buffers(audioGroup, (multi_buffer_list*)arg);
 
 		case B_MULTI_BUFFER_EXCHANGE:
-			return buffer_exchange(audioGroup, arg);
+			return buffer_exchange(audioGroup, (multi_buffer_info*)arg);
 		case B_MULTI_BUFFER_FORCE_STOP:
 			return buffer_force_stop(audioGroup);