Hi,
I have seen some network hangs with my gem(4) interface on sparc64.
Receiving packets stopped sometimes, ifconfig down/up made it work
again.
In the tick timeout handler refill the receive ring if it is empty.
The logic is taken from hme(4). Also splnet() should protect the
register access and ifp counters.
As this did not help, I looked into gem_rx_watchdog(). There is a
workaround for a hardware bug. It resets the hardware when there
is no progress. I my case the fifo pointers advanced a bit, but
finally got stuck anyway. So I restart the receive watchdog timeout
again.
Since this fix the interface keeps running.
ok?
bluhm
Index: dev/ic/gem.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/dev/ic/gem.c,v
retrieving revision 1.122
diff -u -p -r1.122 gem.c
--- dev/ic/gem.c 8 Jun 2017 01:34:00 -0000 1.122
+++ dev/ic/gem.c 3 Feb 2018 16:49:36 -0000
@@ -423,6 +423,7 @@ gem_tick(void *arg)
int s;
u_int32_t v;
+ s = splnet();
/* unload collisions counters */
v = bus_space_read_4(t, mac, GEM_MAC_EXCESS_COLL_CNT) +
bus_space_read_4(t, mac, GEM_MAC_LATE_COLL_CNT);
@@ -448,7 +449,15 @@ gem_tick(void *arg)
bus_space_write_4(t, mac, GEM_MAC_RX_CRC_ERR_CNT, 0);
bus_space_write_4(t, mac, GEM_MAC_RX_CODE_VIOL, 0);
- s = splnet();
+ /*
+ * If buffer allocation fails, the receive ring may become
+ * empty. There is no receive interrupt to recover from that.
+ */
+ if (if_rxr_inuse(&sc->sc_rx_ring) == 0) {
+ gem_fill_rx_ring(sc);
+ bus_space_write_4(t, mac, GEM_RX_KICK, sc->sc_rx_prod);
+ }
+
mii_tick(&sc->sc_mii);
splx(s);
@@ -1200,17 +1209,26 @@ gem_rx_watchdog(void *arg)
rx_fifo_wr_ptr = bus_space_read_4(t, h, GEM_RX_FIFO_WR_PTR);
rx_fifo_rd_ptr = bus_space_read_4(t, h, GEM_RX_FIFO_RD_PTR);
state = bus_space_read_4(t, h, GEM_MAC_MAC_STATE);
- if ((state & GEM_MAC_STATE_OVERFLOW) == GEM_MAC_STATE_OVERFLOW &&
- ((rx_fifo_wr_ptr == rx_fifo_rd_ptr) ||
- ((sc->sc_rx_fifo_wr_ptr == rx_fifo_wr_ptr) &&
- (sc->sc_rx_fifo_rd_ptr == rx_fifo_rd_ptr)))) {
- /*
- * The RX state machine is still in overflow state and
- * the RX FIFO write and read pointers seem to be
- * stuck. Whack the chip over the head to get things
- * going again.
- */
- gem_init(ifp);
+ if ((state & GEM_MAC_STATE_OVERFLOW) == GEM_MAC_STATE_OVERFLOW) {
+ if ((rx_fifo_wr_ptr == rx_fifo_rd_ptr) ||
+ ((sc->sc_rx_fifo_wr_ptr == rx_fifo_wr_ptr) &&
+ (sc->sc_rx_fifo_rd_ptr == rx_fifo_rd_ptr))) {
+ /*
+ * The RX state machine is still in overflow state and
+ * the RX FIFO write and read pointers seem to be
+ * stuck. Whack the chip over the head to get things
+ * going again.
+ */
+ gem_init(ifp);
+ } else {
+ /*
+ * We made some progress, but is not certain that the
+ * overflow condition has been resolved. Check again.
+ */
+ sc->sc_rx_fifo_wr_ptr = rx_fifo_wr_ptr;
+ sc->sc_rx_fifo_rd_ptr = rx_fifo_rd_ptr;
+ timeout_add_msec(&sc->sc_rx_watchdog, 400);
+ }
}
}
