diff options
| author |   Christian Lamparter <chunkeey@googlemail.com> | 2012-09-11 23:18:34 +0200 |
|---|---|---|
| committer |   John W. Linville <linville@tuxdriver.com> | 2012-10-29 15:18:04 -0400 |
| commit | e0509d3bdd7365d06c9bf570bf9f118cae6cbd58 (patch) | |
| tree | e2a5d8d6d5c8e6a5558d11662853d4cd893f30a0 | |
| parent | Merge tag 'nfc-next-3.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/nfc-3.0 (diff) | |
| download | linux-dev-e0509d3bdd7365d06c9bf570bf9f118cae6cbd58.tar.xz linux-dev-e0509d3bdd7365d06c9bf570bf9f118cae6cbd58.zip | |
carl9170: fix spurious transmissions in sniffer mode
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@sipsolutions.net>
Reported-by: Marco Fonseca <marco@tampabay.rr.com>
Reported-by: Janusz Dziedzic <janusz.dziedzic@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
| -rw-r--r-- | drivers/net/wireless/ath/carl9170/mac.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/drivers/net/wireless/ath/carl9170/mac.c b/drivers/net/wireless/ath/carl9170/mac.c index e3b1b6e87760..24d75ab94f0d 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; } |