Several people have complained about an unusual and undocumented feature of the AR9170 hardware: In siffer mode, the hardware generates spurious ACK frames for every received frame... even broadcasts. The reason for this malfunction is unknown: <http://marc.info/?l=linux-wireless&m=134517238506033> But there's a workaround: Instead of the special sniffer mode, the hardware will be put into station mode and all rx filters are disabled. Reported-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> Reported-by: Marco Fonseca <marco@xxxxxxxxxxxxxxx> Reported-by: Janusz Dziedzic <janusz.dziedzic@xxxxxxxxx> Signed-off-by: Christian Lamparter <chunkeey@xxxxxxxxxxxxxx> --- drivers/net/wireless/ath/carl9170/mac.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/net/wireless/ath/carl9170/mac.c b/drivers/net/wireless/ath/carl9170/mac.c index e3b1b6e..24d75ab 100644 --- a/drivers/net/wireless/ath/carl9170/mac.c +++ b/drivers/net/wireless/ath/carl9170/mac.c @@ -343,7 +343,24 @@ int carl9170_set_operating_mode(struct ar9170 *ar) break; } } else { - mac_addr = NULL; + /* + * Enable monitor mode + * + * rx_ctrl |= AR9170_MAC_RX_CTRL_ACK_IN_SNIFFER; + * sniffer |= AR9170_MAC_SNIFFER_ENABLE_PROMISC; + * + * When the hardware is in SNIFFER_PROMISC mode, + * it generates spurious ACKs for every incoming + * frame. This confuses every peer in the + * vicinity and the network throughput will suffer + * badly. + * + * Hence, the hardware will be put into station + * mode and just the rx filters are disabled. + */ + cam_mode |= AR9170_MAC_CAM_STA; + rx_ctrl |= AR9170_MAC_RX_CTRL_PASS_TO_HOST; + mac_addr = common->macaddr; bssid = NULL; } rcu_read_unlock(); @@ -355,8 +372,6 @@ int carl9170_set_operating_mode(struct ar9170 *ar) enc_mode |= AR9170_MAC_ENCRYPTION_RX_SOFTWARE; if (ar->sniffer_enabled) { - rx_ctrl |= AR9170_MAC_RX_CTRL_ACK_IN_SNIFFER; - sniffer |= AR9170_MAC_SNIFFER_ENABLE_PROMISC; enc_mode |= AR9170_MAC_ENCRYPTION_RX_SOFTWARE; } -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
