diff --git a/board/grunt/usb_pd_policy.c b/board/grunt/usb_pd_policy.c
index 3f873beee4..52f9f9450c 100644
--- a/board/grunt/usb_pd_policy.c
+++ b/board/grunt/usb_pd_policy.c
@@ -313,39 +313,81 @@ static int svdm_dp_config(int port, uint32_t *payload)
 	return 2;
 };
 
+/*
+ * timestamp of the next possible toggle to ensure the 2-ms spacing
+ * between IRQ_HPD.
+ */
+static uint64_t hpd_deadline[CONFIG_USB_PD_PORT_COUNT];
+
+#define PORT_TO_HPD(port) ((port) ? GPIO_USB_C1_DP_HPD : GPIO_USB_C0_DP_HPD)
 static void svdm_dp_post_config(int port)
 {
-	const struct usb_mux *mux = &usb_muxes[port];
+	const struct usb_mux * const mux = &usb_muxes[port];
 
 	dp_flags[port] |= DP_FLAGS_DP_ON;
 	if (!(dp_flags[port] & DP_FLAGS_HPD_HI_PENDING))
 		return;
+
+	gpio_set_level(PORT_TO_HPD(port), 1);
+
+	/* set the minimum time delay (2ms) for the next HPD IRQ */
+	hpd_deadline[port] = get_time().val + HPD_USTREAM_DEBOUNCE_LVL;
 	mux->hpd_update(port, 1, 0);
 }
 
 static int svdm_dp_attention(int port, uint32_t *payload)
 {
+	int cur_lvl;
 	int lvl = PD_VDO_DPSTS_HPD_LVL(payload[1]);
 	int irq = PD_VDO_DPSTS_HPD_IRQ(payload[1]);
-	const struct usb_mux *mux = &usb_muxes[port];
+	enum gpio_signal hpd = PORT_TO_HPD(port);
+	const struct usb_mux * const mux = &usb_muxes[port];
 
+	cur_lvl = gpio_get_level(hpd);
 	dp_status[port] = payload[1];
+
+	/* Its initial DP status message prior to config */
 	if (!(dp_flags[port] & DP_FLAGS_DP_ON)) {
 		if (lvl)
 			dp_flags[port] |= DP_FLAGS_HPD_HI_PENDING;
-		return 1;
+		return 1; /* ack */
+	}
+
+	if (irq && cur_lvl) {
+		uint64_t now = get_time().val;
+		/* wait for the minimum spacing between IRQ_HPD if needed */
+		if (now < hpd_deadline[port])
+			usleep(hpd_deadline[port] - now);
+
+		/* generate IRQ_HPD pulse */
+		gpio_set_level(hpd, 0);
+		usleep(HPD_DSTREAM_DEBOUNCE_IRQ);
+		gpio_set_level(hpd, 1);
+
+		/* set the minimum time delay (2ms) for the next HPD IRQ */
+		hpd_deadline[port] = get_time().val + HPD_USTREAM_DEBOUNCE_LVL;
+	} else if (irq && !cur_lvl) {
+		/*
+		 * IRQ can only be generated when the level is high, because
+		 * the IRQ is signaled by a short low pulse from the high level.
+		 */
+		CPRINTF("ERR:HPD:IRQ&LOW\n");
+		return 0; /* nak */
+	} else {
+		gpio_set_level(hpd, lvl);
+		/* set the minimum time delay (2ms) for the next HPD IRQ */
+		hpd_deadline[port] = get_time().val + HPD_USTREAM_DEBOUNCE_LVL;
 	}
 	mux->hpd_update(port, lvl, irq);
-
-	/* ack */
-	return 1;
+	return 1; /* ack */
 }
 
 static void svdm_exit_dp_mode(int port)
 {
-	const struct usb_mux *mux = &usb_muxes[port];
+	const struct usb_mux * const mux = &usb_muxes[port];
 
 	svdm_safe_dp_mode(port);
+	gpio_set_level(PORT_TO_HPD(port), 0);
 	mux->hpd_update(port, 0, 0);
 }