Limit the number of dma segments used for transmitting packets to

IWM_NUM_OF_TBS - 2.  We have IWM_NUM_OF_TBS slots, but use two of those
for sending commands to the firmware.  Hopefully fixes the

  iwm0: hardware error, stopping device

errors I've seen somewhat regularly.

ok claudio@, deraadt@

diff --git a/sys/dev/pci/if_iwm.c b/sys/dev/pci/if_iwm.c
index 00ca532..adb334f 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 1.40 2015/05/21 22:13:55 kettenis Exp $    */
+/*     $OpenBSD: if_iwm.c,v 1.41 2015/05/22 06:50:54 kettenis Exp $    */
 
 /*
  * Copyright (c) 2014 genua mbh <info@genua.de>
@@ -1113,7 +1113,8 @@ iwm_alloc_tx_ring(struct iwm_softc *sc, struct iwm_tx_ring *ring, int qid)
                paddr += sizeof(struct iwm_device_cmd);
 
                error = bus_dmamap_create(sc->sc_dmat, MCLBYTES,
-                   IWM_NUM_OF_TBS, MCLBYTES, 0, BUS_DMA_NOWAIT, &data->map);
+                   IWM_NUM_OF_TBS - 2, MCLBYTES, 0, BUS_DMA_NOWAIT,
+                   &data->map);
                if (error != 0) {
                        printf("%s: could not create TX buf DMA map\n", DEVNAME(sc));
                        goto fail;