Stop running iwm(4) devices in "continuous active mode (CAM)".

Instead, enable device-level power saving which apparently allows
Tx/Rx RF circuitry to be switched off while inactive to save some power.
Turns out CAM is meant for debugging purposes, not normal operation.

NB: This has nothing to do with 802.11 power saving.

Tested by myself and phessler. There is no visible behaviour change.
ok deraadt@ phessler@

diff --git a/sys/dev/pci/if_iwm.c b/sys/dev/pci/if_iwm.c
index ead82d7..0ce72d2 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 1.221 2017/12/08 21:16:01 stsp Exp $       */
+/*     $OpenBSD: if_iwm.c,v 1.222 2017/12/10 20:34:41 stsp Exp $       */
 
 /*
  * Copyright (c) 2014, 2016 genua gmbh <info@genua.de>
@@ -4498,11 +4498,7 @@ iwm_power_build_cmd(struct iwm_softc *sc, struct iwm_node *in,
        keep_alive = roundup(keep_alive, 1000) / 1000;
        cmd->keep_alive_seconds = htole16(keep_alive);
 
-#ifdef notyet
        cmd->flags = htole16(IWM_POWER_FLAGS_POWER_SAVE_ENA_MSK);
-       cmd->rx_data_timeout = IWM_DEFAULT_PS_RX_DATA_TIMEOUT;
-       cmd->tx_data_timeout = IWM_DEFAULT_PS_TX_DATA_TIMEOUT;
-#endif
 }
 
 int
@@ -4530,16 +4526,12 @@ int
 iwm_power_update_device(struct iwm_softc *sc)
 {
        struct iwm_device_power_cmd cmd = {
-#ifdef notyet
                .flags = htole16(IWM_DEVICE_POWER_FLAGS_POWER_SAVE_ENA_MSK),
-#endif
        };
 
        if (!(sc->sc_capaflags & IWM_UCODE_TLV_FLAGS_DEVICE_PS_CMD))
                return 0;
 
-       cmd.flags |= htole16(IWM_DEVICE_POWER_FLAGS_CAM_MSK);
-
        return iwm_send_cmd_pdu(sc,
            IWM_POWER_TABLE_CMD, 0, sizeof(cmd), &cmd);
 }