diff --git a/Documentation/pps/pps.txt b/Documentation/pps/pps.txt
index d35dcdd..c03b1be 100644
--- a/Documentation/pps/pps.txt
+++ b/Documentation/pps/pps.txt
@@ -66,6 +66,21 @@
 into files /dev/pps0, /dev/pps1, etc..
 
 
+PPS with USB to serial devices
+------------------------------
+
+It is possible to grab the PPS from an USB to serial device. However,
+you should take into account the latencies and jitter introduced by
+the USB stack. Users has reported clock instability around +-1ms when
+synchronized with PPS through USB. This isn't suited for time server
+synchronization.
+
+If your device doesn't report PPS, you can check that the feature is
+supported by its driver. Most of the time, you only need to add a call
+to usb_serial_handle_dcd_change after checking the DCD status (see
+ch341 and pl2303 examples).
+
+
 Coding example
 --------------
 
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 1f31e6b..3a5dac8 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -570,6 +570,16 @@
 
 	dev_dbg(&usb_port->dev, "%s - status %d\n", __func__, status);
 
+	if (tty) {
+		struct tty_ldisc *ld = tty_ldisc_ref(tty);
+
+		if (ld) {
+			if (ld->ops->dcd_change)
+				ld->ops->dcd_change(tty, status);
+			tty_ldisc_deref(ld);
+		}
+	}
+
 	if (status)
 		wake_up_interruptible(&port->open_wait);
 	else if (tty && !C_CLOCAL(tty))