diff --git a/sys/dev/usb/serial/u3g.c b/sys/dev/usb/serial/u3g.c
index 9988347243c..0aa26bbffe0 100644
--- a/sys/dev/usb/serial/u3g.c
+++ b/sys/dev/usb/serial/u3g.c
@@ -1100,6 +1100,7 @@ u3g_cfg_get_status(struct ucom_softc *ucom, uint8_t *lsr, uint8_t *msr)
 {
 	struct u3g_softc *sc = ucom->sc_parent;
 
+	/* XXX Note: sc_lsr is always zero */
 	*lsr = sc->sc_lsr[ucom->sc_subunit];
 	*msr = sc->sc_msr[ucom->sc_subunit];
 }
diff --git a/sys/dev/usb/serial/uark.c b/sys/dev/usb/serial/uark.c
index e0e6d0bc904..a1c8976494b 100644
--- a/sys/dev/usb/serial/uark.c
+++ b/sys/dev/usb/serial/uark.c
@@ -427,6 +427,7 @@ uark_cfg_get_status(struct ucom_softc *ucom, uint8_t *lsr, uint8_t *msr)
 {
 	struct uark_softc *sc = ucom->sc_parent;
 
+	/* XXX Note: sc_lsr is always zero */
 	*lsr = sc->sc_lsr;
 	*msr = sc->sc_msr;
 }
diff --git a/sys/dev/usb/serial/uchcom.c b/sys/dev/usb/serial/uchcom.c
index d1063fd4f63..e3fdeedc8a2 100644
--- a/sys/dev/usb/serial/uchcom.c
+++ b/sys/dev/usb/serial/uchcom.c
@@ -625,6 +625,7 @@ uchcom_cfg_get_status(struct ucom_softc *ucom, uint8_t *lsr, uint8_t *msr)
 
 	DPRINTF("\n");
 
+	/* XXX Note: sc_lsr is always zero */
 	*lsr = sc->sc_lsr;
 	*msr = sc->sc_msr;
 }
diff --git a/sys/dev/usb/serial/ufoma.c b/sys/dev/usb/serial/ufoma.c
index fb526cd57e6..dfb41e1871d 100644
--- a/sys/dev/usb/serial/ufoma.c
+++ b/sys/dev/usb/serial/ufoma.c
@@ -900,6 +900,7 @@ ufoma_cfg_get_status(struct ucom_softc *ucom, uint8_t *lsr, uint8_t *msr)
 {
 	struct ufoma_softc *sc = ucom->sc_parent;
 
+	/* XXX Note: sc_lsr is always zero */
 	*lsr = sc->sc_lsr;
 	*msr = sc->sc_msr;
 }
diff --git a/sys/dev/usb/serial/umodem.c b/sys/dev/usb/serial/umodem.c
index 5e65c12e1cb..b9f798b479a 100644
--- a/sys/dev/usb/serial/umodem.c
+++ b/sys/dev/usb/serial/umodem.c
@@ -558,6 +558,7 @@ umodem_cfg_get_status(struct ucom_softc *ucom, uint8_t *lsr, uint8_t *msr)
 
 	DPRINTF("\n");
 
+	/* XXX Note: sc_lsr is always zero */
 	*lsr = sc->sc_lsr;
 	*msr = sc->sc_msr;
 }
diff --git a/sys/dev/usb/serial/uplcom.c b/sys/dev/usb/serial/uplcom.c
index 6e238758fa2..dfc0933d4f0 100644
--- a/sys/dev/usb/serial/uplcom.c
+++ b/sys/dev/usb/serial/uplcom.c
@@ -807,6 +807,7 @@ uplcom_cfg_get_status(struct ucom_softc *ucom, uint8_t *lsr, uint8_t *msr)
 
 	DPRINTF("\n");
 
+	/* XXX Note: sc_lsr is always zero */
 	*lsr = sc->sc_lsr;
 	*msr = sc->sc_msr;
 }
diff --git a/sys/dev/usb/serial/uslcom.c b/sys/dev/usb/serial/uslcom.c
index b516bdec364..063f715eb8f 100644
--- a/sys/dev/usb/serial/uslcom.c
+++ b/sys/dev/usb/serial/uslcom.c
@@ -704,6 +704,7 @@ uslcom_get_status(struct ucom_softc *ucom, uint8_t *lsr, uint8_t *msr)
 
 	DPRINTF("\n");
 
+	/* XXX Note: sc_lsr is always zero */
 	*lsr = sc->sc_lsr;
 	*msr = sc->sc_msr;
 }