urtw(4) contains panic calls in error paths, which are counterproductive,
if not dangerous.
I have a urtw device with a dying connector which doesn't attach
most of the time but will sometimes attach if wiggled a bit.
Without the diff below, the device triggers a panic rather quickly,
such as "unsupported RF chip".
With the diff the device works fine if it happens to attach, and only
as long as it is not touched while operating.
Index: if_urtw.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/if_urtw.c,v
retrieving revision 1.53
diff -u -p -r1.53 if_urtw.c
--- if_urtw.c 12 Jun 2015 15:47:31 -0000 1.53
+++ if_urtw.c 15 Jul 2015 05:08:25 -0000
@@ -1252,8 +1252,7 @@ urtw_get_rfchip(struct urtw_softc *sc)
if (sc->sc_hwrev & URTW_HWREV_8187) {
error = urtw_eprom_read32(sc, URTW_EPROM_RFCHIPID, &data);
if (error != 0)
- panic("unsupported RF chip");
- /* NOTREACHED */
+ goto fail;
switch (data & 0xff) {
case URTW_EPROM_RFCHIPID_RTL8225U:
error = urtw_8225_isv2(sc, &ret);
@@ -1286,8 +1285,8 @@ urtw_get_rfchip(struct urtw_softc *sc)
return (0);
fail:
- panic("unsupported RF chip %d", data & 0xff);
- /* NOTREACHED */
+ printf("unsupported RF chip %d", data & 0xff);
+ return (error);
}
usbd_status
@@ -1793,7 +1792,7 @@ fail:
usbd_status
urtw_led_on(struct urtw_softc *sc, int type)
{
- usbd_status error;
+ usbd_status error = 0;
if (type == URTW_LED_GPIO) {
switch (sc->sc_gpio_ledpin) {
@@ -1802,13 +1801,8 @@ urtw_led_on(struct urtw_softc *sc, int t
urtw_write8_m(sc, URTW_GP_ENABLE, 0x00);
break;
default:
- panic("unsupported LED PIN type 0x%x",
- sc->sc_gpio_ledpin);
- /* NOTREACHED */
+ break;
}
- } else {
- panic("unsupported LED type 0x%x", type);
- /* NOTREACHED */
}
sc->sc_gpio_ledon = 1;
@@ -1819,7 +1813,7 @@ fail:
static usbd_status
urtw_led_off(struct urtw_softc *sc, int type)
{
- usbd_status error;
+ usbd_status error = 0;
if (type == URTW_LED_GPIO) {
switch (sc->sc_gpio_ledpin) {
@@ -1828,13 +1822,8 @@ urtw_led_off(struct urtw_softc *sc, int
urtw_write8_m(sc, URTW_GP_ENABLE, 0x01);
break;
default:
- panic("unsupported LED PIN type 0x%x",
- sc->sc_gpio_ledpin);
- /* NOTREACHED */
+ break;
}
- } else {
- panic("unsupported LED type 0x%x", type);
- /* NOTREACHED */
}
sc->sc_gpio_ledon = 0;
@@ -1863,8 +1852,7 @@ urtw_led_mode0(struct urtw_softc *sc, in
sc->sc_gpio_ledstate = URTW_LED_ON;
break;
default:
- panic("unsupported LED mode 0x%x", mode);
- /* NOTREACHED */
+ break;
}
switch (sc->sc_gpio_ledstate) {
@@ -1890,8 +1878,7 @@ urtw_led_mode0(struct urtw_softc *sc, in
urtw_led_off(sc, URTW_LED_GPIO);
break;
default:
- panic("unknown LED status 0x%x", sc->sc_gpio_ledstate);
- /* NOTREACHED */
+ break;
}
return (0);
}
@@ -1920,7 +1907,7 @@ urtw_ledusbtask(void *arg)
struct urtw_softc *sc = arg;
if (sc->sc_strategy != URTW_SW_LED_MODE0)
- panic("could not process a LED strategy 0x%x", sc->sc_strategy);
+ return;
urtw_led_blink(sc);
}
@@ -1956,8 +1943,7 @@ urtw_led_ctl(struct urtw_softc *sc, int
error = urtw_led_mode3(sc, mode);
break;
default:
- panic("unsupported LED mode %d", sc->sc_strategy);
- /* NOTREACHED */
+ break;
}
return (error);
@@ -2007,8 +1993,7 @@ urtw_led_blink(struct urtw_softc *sc)
timeout_add(&sc->sc_led_ch, tvtohz(&t));
break;
default:
- panic("unknown LED status 0x%x", sc->sc_gpio_ledstate);
- /* NOTREACHED */
+ break;
}
return (0);
}
@@ -2034,9 +2019,7 @@ urtw_update_msr(struct urtw_softc *sc)
data |= URTW_MSR_LINK_STA;
break;
default:
- panic("unsupported operation mode 0x%x",
- ic->ic_opmode);
- /* NOTREACHED */
+ break;
}
} else
data |= URTW_MSR_LINK_NONE;
@@ -2666,7 +2649,7 @@ urtw_tx_start(struct urtw_softc *sc, str
data->buf[2] |= 1;
if ((m0->m_pkthdr.len > ic->ic_rtsthreshold) &&
prior == URTW_PRIORITY_LOW)
- panic("TODO tx.");
+ return ENOTSUP; /* TODO */
if (wh->i_fc[1] & IEEE80211_FC1_MORE_FRAG)
data->buf[2] |= (1 << 1);
/* RTS rate - 10 means we use a basic rate. */
