On 03/02/18(Sat) 18:08, Alexander Bluhm wrote:
> 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?
I've seen this problem sporadically on macppc has well. So ok with me.
> 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);
> + }
> }
> }
>
>
