diff --git a/board/dingdong/board.h b/board/dingdong/board.h
index c814b6f48d..814df199bc 100644
--- a/board/dingdong/board.h
+++ b/board/dingdong/board.h
@@ -21,6 +21,7 @@
 #define CONFIG_HW_CRC
 #define CONFIG_USB
 #define CONFIG_USB_BOS
+#define CONFIG_USB_INHIBIT
 #define CONFIG_USB_POWER_DELIVERY
 #define CONFIG_USB_PD_ALT_MODE
 #define CONFIG_USB_PD_DUAL_ROLE
diff --git a/board/dingdong/usb_pd_policy.c b/board/dingdong/usb_pd_policy.c
index 2e18792733..5894427ca8 100644
--- a/board/dingdong/usb_pd_policy.c
+++ b/board/dingdong/usb_pd_policy.c
@@ -13,6 +13,7 @@
 #include "task.h"
 #include "timer.h"
 #include "util.h"
+#include "usb.h"
 #include "usb_pd.h"
 #include "version.h"
 
@@ -145,10 +146,8 @@ const uint32_t vdo_dp_mode[MODE_CNT] =  {
 
 static int svdm_response_modes(int port, uint32_t *payload)
 {
-	if (PD_VDO_VID(payload[0]) != USB_SID_DISPLAYPORT) {
-		/* TODO(tbroch) USB billboard enabled here then */
-		return 1; /* will generate a NAK */
-	}
+	if (PD_VDO_VID(payload[0]) != USB_SID_DISPLAYPORT)
+		return 0; /* nak */
 
 	memcpy(payload + 1, vdo_dp_mode, sizeof(vdo_dp_mode));
 	return MODE_CNT + 1;
@@ -187,11 +186,12 @@ static int svdm_enter_mode(int port, uint32_t *payload)
 	    (PD_VDO_OPOS(payload[0]) != OPOS))
 		return 0; /* will generate NAK */
 
+	/* TODO(tbroch) Enumerate USB BB here with updated mode choice */
 	alt_mode = OPOS;
 	return 1;
 }
 
-int pd_alt_mode(int port)
+int pd_alt_mode(void)
 {
 	return alt_mode;
 }
diff --git a/board/hoho/board.h b/board/hoho/board.h
index c341b479fe..d98ba5b135 100644
--- a/board/hoho/board.h
+++ b/board/hoho/board.h
@@ -29,6 +29,7 @@
 #define CONFIG_SPI_CS_GPIO GPIO_PD_MCDP_SPI_CS_L
 #define CONFIG_USB
 #define CONFIG_USB_BOS
+#define CONFIG_USB_INHIBIT
 #define CONFIG_USB_POWER_DELIVERY
 #define CONFIG_USB_PD_ALT_MODE
 #define CONFIG_USB_PD_DUAL_ROLE
diff --git a/board/hoho/usb_pd_policy.c b/board/hoho/usb_pd_policy.c
index 4eff69b49e..3da52023c3 100644
--- a/board/hoho/usb_pd_policy.c
+++ b/board/hoho/usb_pd_policy.c
@@ -12,6 +12,7 @@
 #include "registers.h"
 #include "task.h"
 #include "timer.h"
+#include "usb.h"
 #include "usb_pd.h"
 #include "util.h"
 #include "version.h"
@@ -145,10 +146,8 @@ const uint32_t vdo_dp_mode[MODE_CNT] =  {
 
 static int svdm_response_modes(int port, uint32_t *payload)
 {
-	if (PD_VDO_VID(payload[0]) != USB_SID_DISPLAYPORT) {
-		/* TODO(tbroch) USB billboard enabled here then */
-		return 1; /* will generate a NAK */
-	}
+	if (PD_VDO_VID(payload[0]) != USB_SID_DISPLAYPORT)
+		return 0; /* nak */
 
 	memcpy(payload + 1, vdo_dp_mode, sizeof(vdo_dp_mode));
 	return MODE_CNT + 1;
@@ -186,11 +185,12 @@ static int svdm_enter_mode(int port, uint32_t *payload)
 	    (PD_VDO_OPOS(payload[0]) != OPOS))
 		return 0; /* will generate a NAK */
 
+	/* TODO(tbroch) Enumerate USB BB here with updated mode choice */
 	alt_mode = OPOS;
 	return 1;
 }
 
-int pd_alt_mode(int port)
+int pd_alt_mode(void)
 {
 	return alt_mode;
 }
diff --git a/chip/stm32/usb.c b/chip/stm32/usb.c
index b9f69ec848..409cb4f69d 100644
--- a/chip/stm32/usb.c
+++ b/chip/stm32/usb.c
@@ -297,20 +297,37 @@ void usb_init(void)
 	/* set interrupts mask : reset/correct tranfer/errors */
 	STM32_USB_CNTR = 0xe400;
 
-	/* set pull-up on DP for FS mode */
-#ifdef CHIP_VARIANT_STM32L15X
-	STM32_SYSCFG_PMC |= 1;
-#elif defined(CHIP_FAMILY_STM32F0)
-	STM32_USB_BCDR |= 1 << 15 /* DPPU */;
-#else
-	/* hardwired or regular GPIO on other platforms */
+#ifndef CONFIG_USB_INHIBIT
+	usb_connect();
 #endif
 
 	CPRINTF("USB init done\n");
 }
-#ifndef CONFIG_USB_INHIBIT
 DECLARE_HOOK(HOOK_INIT, usb_init, HOOK_PRIO_DEFAULT);
+
+void usb_disconnect(void)
+{
+	/* disable pull-up on DP to disconnect */
+#ifdef CHIP_VARIANT_STM32L15X
+	STM32_SYSCFG_PMC &= ~1;
+#elif defined(CHIP_FAMILY_STM32F0)
+	STM32_USB_BCDR &= ~(1 << 15) /* DPPU */;
+#else
+#warn "usb disconnect not implemented for this chip family"
 #endif
+}
+
+void usb_connect(void)
+{
+	/* enable pull-up on DP to connect */
+#ifdef CHIP_VARIANT_STM32L15X
+	STM32_SYSCFG_PMC |= 1;
+#elif defined(CHIP_FAMILY_STM32F0)
+	STM32_USB_BCDR |= (1 << 15) /* DPPU */;
+#else
+#warn "usb connect not implemented for this chip family"
+#endif
+}
 
 void usb_release(void)
 {
diff --git a/common/usb_pd_policy.c b/common/usb_pd_policy.c
index f0ae2cffab..87e1062817 100644
--- a/common/usb_pd_policy.c
+++ b/common/usb_pd_policy.c
@@ -7,11 +7,13 @@
 #include "common.h"
 #include "console.h"
 #include "gpio.h"
+#include "hooks.h"
 #include "host_command.h"
 #include "registers.h"
 #include "task.h"
 #include "timer.h"
 #include "util.h"
+#include "usb.h"
 #include "usb_pd.h"
 #include "usb_pd_config.h"
 #include "version.h"
@@ -382,10 +384,6 @@ int pd_svdm(int port, int cnt, uint32_t *payload, uint32_t **rpayload)
 	return 0;
 }
 
-int pd_alt_mode(int port)
-{
-	return 0;
-}
 #endif /* CONFIG_USB_PD_ALT_MODE */
 
 #ifndef CONFIG_USB_PD_CUSTOM_VDM
@@ -395,6 +393,18 @@ int pd_vdm(int port, int cnt, uint32_t *payload, uint32_t **rpayload)
 }
 #endif /* !CONFIG_USB_PD_CUSTOM_VDM */
 
+void pd_usb_billboard_deferred(void)
+{
+#if defined(CONFIG_USB_PD_ALT_MODE) && !defined(CONFIG_USB_PD_ALT_MODE_DFP) \
+	&& !defined(CONFIG_USB_PD_SIMPLE_DFP)
+
+	if (!pd_alt_mode())
+		usb_connect();
+
+#endif
+}
+DECLARE_DEFERRED(pd_usb_billboard_deferred);
+
 #ifndef CONFIG_USB_PD_ALT_MODE_DFP
 int pd_exit_mode(int port, uint32_t *payload)
 {
diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index c91893c4c5..c44e070043 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -185,6 +185,9 @@ static const uint8_t dec4b5b[] = {
 #define PD_T_DRP_SRC           (30*MSEC) /* toggle time for source DRP */
 #define PD_T_SRC_RECOVER      (760*MSEC) /* between 660ms and 1000ms */
 
+/* from USB Type-C Specification Table 5-1 */
+#define PD_T_AME (1*SECOND) /* timeout from UFP attach to Alt Mode Entry */
+
 /* Port role at startup */
 #ifdef CONFIG_USB_PD_DUAL_ROLE
 #define PD_ROLE_DEFAULT PD_ROLE_SINK
@@ -1464,6 +1467,9 @@ void pd_task(void)
 #endif
 					set_state(port, PD_STATE_SNK_DISCOVERY);
 					timeout = 10*MSEC;
+					hook_call_deferred(
+						pd_usb_billboard_deferred,
+						PD_T_AME);
 					break;
 				}
 			}
@@ -1750,7 +1756,7 @@ static int remote_flashing(int argc, char **argv)
 void pd_send_hpd(int port, enum hpd_event hpd)
 {
 	uint32_t data[1];
-	int opos = pd_alt_mode(port);
+	int opos = pd_alt_mode();
 	if (!opos)
 		return;
 
diff --git a/include/usb.h b/include/usb.h
index df6426fc64..bce830ebb3 100644
--- a/include/usb.h
+++ b/include/usb.h
@@ -296,6 +296,8 @@ extern void (*usb_iface_request[]) (usb_uint *ep0_buf_rx, usb_uint *ep0_buf_tx);
 
 /* functions to start/stop USB */
 void usb_init(void);
+void usb_disconnect(void);
+void usb_connect(void);
 void usb_release(void);
 
 #endif /* USB_H */
diff --git a/include/usb_pd.h b/include/usb_pd.h
index c13e5e9588..072f070359 100644
--- a/include/usb_pd.h
+++ b/include/usb_pd.h
@@ -784,10 +784,9 @@ void board_flip_usb_mux(int port);
 /**
  * Determine if in alternate mode or not.
  *
- * @param port port number.
  * @return object position of mode chosen in alternate mode otherwise zero.
  */
-int pd_alt_mode(int port);
+int pd_alt_mode(void);
 
 /**
  * Send hpd over USB PD.
@@ -796,6 +795,11 @@ int pd_alt_mode(int port);
  * @param hpd hotplug detect type.
  */
 void pd_send_hpd(int port, enum hpd_event hpd);
+
+/**
+ * Enable USB Billboard Device.
+ */
+void pd_usb_billboard_deferred(void);
 /* --- Physical layer functions : chip specific --- */
 
 /* Packet preparation/retrieval */