Reset the Tx timer when iwm(4) firmware sends a BA notification.

This prevents a bogus "device timeout" if firmware sends a IWM_BA_NOTIF
instead of IWM_TX_CMD in order to let us know that a frame has been sent
on a Tx aggregation queue. Such behaviour was observed on iwx(4), and there
is reason to believe that iwm(4) might also be affected by this issue.

Tested by Jean-Michel Bessot on 7265 via bugs@ where this change seems
to prevent random device timeouts.
Tested by myself on 8265 with no apparent behaviour change seen.

diff --git a/sys/dev/pci/if_iwm.c b/sys/dev/pci/if_iwm.c
index 58d7c6d..cb75fbf 100644 (file)
--- a/sys/dev/pci/if_iwm.c
+++ b/sys/dev/pci/if_iwm.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_iwm.c,v 1.367 2021/09/08 13:06:23 stsp Exp $       */
+/*     $OpenBSD: if_iwm.c,v 1.368 2021/09/24 19:02:16 stsp Exp $       */
 
 /*
  * Copyright (c) 2014, 2016 genua gmbh <info@genua.de>
@@ -5720,6 +5720,8 @@ iwm_rx_compressed_ba(struct iwm_softc *sc, struct iwm_rx_packet *pkt,
        if (qid != IWM_FIRST_AGG_TX_QUEUE + ban->tid)
                return;
 
+       sc->sc_tx_timer = 0;
+
        ba = &ni->ni_tx_ba[ban->tid];
        if (ba->ba_state != IEEE80211_BA_AGREED)
                return;