diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8b91ef0..b6f98fd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,6 +9,7 @@ include(Fxconv)
 option(GINT_NO_OS_STACK "Do not use the OS stack as a memory pool (fx-CG only)")
 option(GINT_STATIC_GRAY "Use static memory instead of malloc for gray buffers (fx-9860G only)")
 option(GINT_KMALLOC_DEBUG "Enable debug functions for kmalloc")
+option(GINT_USB_DEBUG "Enable debug functions for the USB driver")
 
 set(CMAKE_INSTALL_MESSAGE LAZY)
 
diff --git a/include/gint/config.h.in b/include/gint/config.h.in
index 33d9bcf..c71c50d 100644
--- a/include/gint/config.h.in
+++ b/include/gint/config.h.in
@@ -38,4 +38,7 @@
    enabled or disabled at runtime. */
 #cmakedefine GINT_KMALLOC_DEBUG
 
+/* GINT_USB_DEBUG: Selects whether USB debug functions are enabled */
+#cmakedefine GINT_USB_DEBUG
+
 #endif /* GINT_CONFIG */
diff --git a/include/gint/usb.h b/include/gint/usb.h
index 07ddba5..95547cd 100644
--- a/include/gint/usb.h
+++ b/include/gint/usb.h
@@ -12,6 +12,7 @@ extern "C" {
 #include <gint/defs/types.h>
 #include <gint/defs/timeout.h>
 #include <gint/gint.h>
+#include <gint/config.h>
 #include <stdarg.h>
 #include <endian.h>
 
@@ -271,6 +272,9 @@ int usb_commit_async(int pipe, gint_call_t callback);
 // USB debugging log
 //---
 
+#ifdef GINT_USB_DEBUG
+#define USB_LOG(...) usb_log(__VA_ARGS__)
+
 /* usb_set_log(): Set the logging function for the USB driver
 
    The USB driver can produce logs, which are mostly useful to troubleshoot
@@ -284,6 +288,10 @@ void usb_set_log(void (*logger)(char const *format, va_list args));
 /* usb_log(): Send a message to the USB log */
 void usb_log(char const *format, ...);
 
+#else
+#define USB_LOG(...) do {} while(0)
+#endif
+
 //---
 // Standard descriptors
 //---
diff --git a/src/usb/configure.c b/src/usb/configure.c
index 953f746..26aef0f 100644
--- a/src/usb/configure.c
+++ b/src/usb/configure.c
@@ -177,25 +177,27 @@ int usb_configure_solve(usb_interface_t const **interfaces)
 	return 0;
 }
 
-/* usb_configure_log(): Print configuration results in the usb_log() */
+/* usb_configure_log(): Print configuration results in the USB_LOG() */
 void usb_configure_log(void)
 {
+#ifdef GINT_USB_DEBUG
 	/* Log the final configuration */
 	for(int i = 0; i < 16 && conf_if[i]; i++)
-		usb_log("Interface #%d: %p\n", i, conf_if[i]);
+		USB_LOG("Interface #%d: %p\n", i, conf_if[i]);
 
 	for(int i = 0; i < 32; i++)
 	{
 		if(!conf_ep[i].intf) continue;
 
 		endpoint_t *ep = &conf_ep[i];
-		usb_log("Endpoint %02x\n",
+		USB_LOG("Endpoint %02x\n",
 			(i & 15) + (i >= 16 ? 0x80 : 0));
-		usb_log("  Interface %p address %02x\n",
+		USB_LOG("  Interface %p address %02x\n",
 			ep->intf, ep->dc->bEndpointAddress);
-		usb_log("  Pipe %d (FIFO: %02x..%02x)\n",
+		USB_LOG("  Pipe %d (FIFO: %02x..%02x)\n",
 			ep->pipe, ep->bufnmb, ep->bufnmb + ep->bufsize);
 	}
+#endif
 }
 
 /* usb_configure(): Load the generated configuration to the USB module */
diff --git a/src/usb/pipes.c b/src/usb/pipes.c
index 1128752..b0799a2 100644
--- a/src/usb/pipes.c
+++ b/src/usb/pipes.c
@@ -76,7 +76,7 @@ static fifo_t fifo_access(int pipe)
 	if(pipe == 0) return CF;
 	/* Find a free controller */
 	if(USB.D0FIFOSEL.CURPIPE == 0) return D0F;
-	usb_log("Wait D0 is unavailable\n");
+	USB_LOG("Wait D0 is unavailable\n");
 	if(USB.D1FIFOSEL.CURPIPE == 0) return D1F;
 
 	return NOF;
@@ -295,7 +295,7 @@ static void write_round(struct transfer volatile *t, int pipe)
 
 		bool ok = dma_transfer_async(channel, block_size, size,
 			t->data, DMA_INC, (void *)FIFO, DMA_FIXED, callback);
-		if(!ok) usb_log("DMA async failed on channel %d!\n", channel);
+		if(!ok) USB_LOG("DMA async failed on channel %d!\n", channel);
 	}
 	else
 	{
@@ -349,7 +349,7 @@ int usb_write_sync_timeout(int pipe, void const *data, int size, int unit_size,
 		if(rc == 0)
 			break;
 		if(rc == USB_WRITE_NOFIFO)
-			usb_log("USB_WRITE_NOFIFO\n");
+			USB_LOG("USB_WRITE_NOFIFO\n");
 		if(rc != USB_WRITE_BUSY)
 			return rc;
 		if(timeout_elapsed(timeout))
@@ -401,7 +401,7 @@ int usb_commit_async(int pipe, gint_call_t callback)
 	fifo_bind(t->ct, pipe, FIFO_WRITE, t->unit_size);
 	if(t->ct == D0F) USB.D0FIFOCTR.BVAL = 1;
 	if(t->ct == D1F) USB.D1FIFOCTR.BVAL = 1;
-	usb_log("[PIPE%d] Committed transfer\n", pipe);
+	USB_LOG("[PIPE%d] Committed transfer\n", pipe);
 
 	return 0;
 }
diff --git a/src/usb/setup.c b/src/usb/setup.c
index 710e283..cd0f54d 100644
--- a/src/usb/setup.c
+++ b/src/usb/setup.c
@@ -88,7 +88,7 @@ static void write_configuration_descriptor(int wLength)
 		uint8_t const *dc = interfaces[i]->dc[k];
 		total_length += dc[0];
 	}
-	usb_log("Configuration descriptor size: %d\n", (int)total_length);
+	USB_LOG("Configuration descriptor size: %d\n", (int)total_length);
 
 	/* Write the configuration descriptor */
 	dc_configuration.wTotalLength = htole16(total_length);
@@ -127,9 +127,9 @@ static void req_get_descriptor(int wValue, int wLength)
 	int type = (wValue >> 8) & 0xff;
 	int num = (wValue & 0xff);
 
-	static char const *strs[] = {
+	GUNUSED static char const *strs[] = {
 		"DEV","CONFIG","STR","INTF","ENDP","DEVQ","OSC","POWER" };
-	usb_log("GET_DESCRIPTOR: %s #%d len:%d\n", strs[type-1], num, wLength);
+	USB_LOG("GET_DESCRIPTOR: %s #%d len:%d\n", strs[type-1], num, wLength);
 
 	if(type == USB_DC_DEVICE && num == 0)
 		dcp_write(&dc_device, dc_device.bLength);
@@ -150,13 +150,13 @@ static void req_get_descriptor(int wValue, int wLength)
 
 static void req_get_configuration(void)
 {
-	usb_log("GET_CONFIGURATION -> %d\n", 1);
+	USB_LOG("GET_CONFIGURATION -> %d\n", 1);
 	dcp_write("\x01", 1);
 }
 
 static void req_set_configuration(int wValue)
 {
-	usb_log("SET_CONFIGURATION: %d\n", wValue);
+	USB_LOG("SET_CONFIGURATION: %d\n", wValue);
 	/* Ok for (wValue == 1) only */
 	USB.DCPCTR.PID = (wValue == 1) ? 1 : 2;
 }
@@ -167,7 +167,7 @@ void usb_req_setup(void)
 	int bRequest = USB.USBREQ.BREQUEST;
 	int bmRequestType = USB.USBREQ.BMREQUEST;
 	int wValue = USB.USBVAL.word;
-	int wIndex = USB.USBINDX.word;
+	GUNUSED int wIndex = USB.USBINDX.word;
 	int wLength = USB.USBLENG.word;
 
 	USB.INTSTS0.VALID = 0;
@@ -185,7 +185,7 @@ void usb_req_setup(void)
 		req_set_configuration(wValue);
 
 	/* TODO: Other standard SETUP requests */
-	else usb_log("SETUP: bRequest=%02x bmRequestType=%02x wValue=%04x\n"
+	else USB_LOG("SETUP: bRequest=%02x bmRequestType=%02x wValue=%04x\n"
 		"  wIndex=%04x wLength=%d -> ???\n",
 		bRequest, bmRequestType, wValue, wIndex, wLength);
 
diff --git a/src/usb/usb.c b/src/usb/usb.c
index 278e8cf..1bf803c 100644
--- a/src/usb/usb.c
+++ b/src/usb/usb.c
@@ -111,14 +111,14 @@ static void hpoweroff(void)
 
 int usb_open(usb_interface_t const **interfaces, gint_call_t callback)
 {
-	usb_log("---- usb_open ----\n");
+	USB_LOG("---- usb_open ----\n");
 
 	int rc = usb_configure_solve(interfaces);
 	usb_configure_log();
 
 	if(rc != 0)
 	{
-		usb_log("configure failure: %d\n", rc);
+		USB_LOG("configure failure: %d\n", rc);
 		return rc;
 	}
 
@@ -189,7 +189,7 @@ void usb_close(void)
 {
 	intc_priority(INTC_USB, 0);
 	hpoweroff();
-	usb_log("---- usb_close ----\n");
+	USB_LOG("---- usb_close ----\n");
 
 	usb_open_callback = GINT_CALL_NULL;
 	usb_open_status = false;
@@ -201,7 +201,7 @@ void usb_close(void)
 
 static void usb_interrupt_handler(void)
 {
-	static char const * const device_st[] = {
+	GUNUSED static char const * const device_st[] = {
 		"powered", "default", "address", "configured",
 		"suspended-powered", "suspended-default", "suspended-address",
 		"suspended-configured",
@@ -212,7 +212,7 @@ static void usb_interrupt_handler(void)
 	if(USB.INTSTS0.VBINT)
 	{
 		INTSTS0_clear(VBINT);
-		usb_log("VBUS %s\n", USB.INTSTS0.VBSTS ? "up" : "down");
+		USB_LOG("VBUS %s\n", USB.INTSTS0.VBSTS ? "up" : "down");
 	}
 	else if(USB.INTSTS0.CTRT)
 	{
@@ -222,9 +222,9 @@ static void usb_interrupt_handler(void)
 	else if(USB.INTSTS0.DVST)
 	{
 		INTSTS0_clear(DVST);
-		usb_log("DVST %s", device_st[USB.INTSTS0.DVSQ]);
-		if(USB.INTSTS0.DVSQ == 2) usb_log(": %04x\n",USB.USBADDR.word);
-		else usb_log("\n");
+		USB_LOG("DVST %s", device_st[USB.INTSTS0.DVSQ]);
+		if(USB.INTSTS0.DVSQ == 2) USB_LOG(": %04x\n",USB.USBADDR.word);
+		else USB_LOG("\n");
 
 		/* When configured, run the callback for usb_open() */
 		if(USB.INTSTS0.DVSQ == 3)
@@ -248,7 +248,7 @@ static void usb_interrupt_handler(void)
 			if(status & (1 << i)) usb_pipe_write_bemp(i);
 		}
 	}
-	else usb_log("<%04X> -> ???\n", USB.INTSTS0.word);
+	else USB_LOG("<%04X> -> ???\n", USB.INTSTS0.word);
 
 	/* Restore PIPESEL which can have been used for transfers */
 	USB.PIPESEL.word = pipesel;
diff --git a/src/usb/usb_private.h b/src/usb/usb_private.h
index 9b8027a..8e997ff 100644
--- a/src/usb/usb_private.h
+++ b/src/usb/usb_private.h
@@ -131,7 +131,7 @@ void usb_pipe_init_transfers(void);
 		GINT_CALL_SET_STOP(&__f)); \
 	if(__t >= 0) timer_start(__t); \
 	while((condition) && __f == 0) {} \
-	if(__f) usb_log("%s: %d: (" #condition ") holds\n", \
+	if(__f) USB_LOG("%s: %d: (" #condition ") holds\n", \
 		__FUNCTION__, __LINE__); \
 	if(__t >= 0) timer_stop(__t); \
 	__f != 0; \