diff options
| author | Kevin Bowling <kbowling@FreeBSD.org> | 2026-08-03 10:28:49 +0000 |
|---|---|---|
| committer | Kevin Bowling <kbowling@FreeBSD.org> | 2026-08-03 10:37:09 +0000 |
| commit | 709426551c6a3607fb5a33f5b8dbb87cfa9c8125 (patch) | |
| tree | 3ca27e9758d514baffa252da1bd6159925b00428 | |
| parent | 1c91c3ae1ec6c65e458f130a95d3119d83ca088e (diff) | |
igc: Work around I225 v1 minimum IPG erratum
I225 v1 cannot receive the minimum inter-packet gap required at
2.5 Gb/s. For affected back-to-back links, Intel recommends using a
15-byte transmit IPG instead of 12 bytes.
Program TIPG.IPGT to 0xb for pre-v2 I225 devices at 2.5 Gb/s and
restore the default at lower speeds. Avoid penalizing fixed I225 and
I226 parts.
MFC after: 2 weeks
| -rw-r--r-- | sys/dev/igc/if_igc.c | 29 | ||||
| -rw-r--r-- | sys/dev/igc/igc_defines.h | 1 |
2 files changed, 30 insertions, 0 deletions
diff --git a/sys/dev/igc/if_igc.c b/sys/dev/igc/if_igc.c index 4a54d8ca7a6c..fa4f427a5710 100644 --- a/sys/dev/igc/if_igc.c +++ b/sys/dev/igc/if_igc.c @@ -128,6 +128,7 @@ static int igc_if_rx_queue_intr_enable(if_ctx_t, uint16_t); static int igc_if_tx_queue_intr_enable(if_ctx_t, uint16_t); static void igc_if_multi_set(if_ctx_t); static void igc_if_update_admin_status(if_ctx_t); +static void igc_apply_i225_ipg_workaround(struct igc_softc *); static void igc_if_debug(if_ctx_t); static void igc_update_stats_counters(struct igc_softc *); static void igc_add_hw_stats(struct igc_softc *); @@ -1401,6 +1402,33 @@ igc_if_timer(if_ctx_t ctx, uint16_t qid) } static void +igc_apply_i225_ipg_workaround(struct igc_softc *sc) +{ + struct igc_hw *hw = &sc->hw; + u32 ipgt, tipg; + + /* + * I225 v1 cannot receive the minimum IPG required at 2.5 Gb/s. + * Intel's documented back-to-back workaround is for the transmitter + * to use a 15-byte IPG instead of 12 bytes. I225 v2 and later have + * the receive-side fix and should retain the standard IPG. + */ + if (!igc_is_device_id_i225(hw) || + hw->revision_id >= IGC_REVISION_2) + return; + + ipgt = sc->link_speed == SPEED_2500 ? IGC_I225_TIPG_IPGT_2P5 : + DEFAULT_82543_TIPG_IPGT_COPPER; + tipg = IGC_READ_REG(hw, IGC_TIPG); + if ((tipg & IGC_TIPG_IPGT_MASK) == ipgt) + return; + + tipg &= ~IGC_TIPG_IPGT_MASK; + tipg |= ipgt; + IGC_WRITE_REG(hw, IGC_TIPG, tipg); +} + +static void igc_if_update_admin_status(if_ctx_t ctx) { struct igc_softc *sc = iflib_get_softc(ctx); @@ -1445,6 +1473,7 @@ igc_if_update_admin_status(if_ctx_t ctx) sc->link_active = 0; iflib_link_state_change(ctx, LINK_STATE_DOWN, 0); } + igc_apply_i225_ipg_workaround(sc); igc_update_stats_counters(sc); } diff --git a/sys/dev/igc/igc_defines.h b/sys/dev/igc/igc_defines.h index 09f75fe2787e..3e6309176204 100644 --- a/sys/dev/igc/igc_defines.h +++ b/sys/dev/igc/igc_defines.h @@ -364,6 +364,7 @@ /* Default values for the transmit IPG register */ #define DEFAULT_82543_TIPG_IPGT_FIBER 9 #define DEFAULT_82543_TIPG_IPGT_COPPER 8 +#define IGC_I225_TIPG_IPGT_2P5 0xB #define IGC_TIPG_IPGT_MASK 0x000003FF |