[PATCH 4.1 069/123] iwlwifi: mvm: fix antenna selection when BT is active

From: Greg Kroah-Hartman
Date: Sat Aug 08 2015 - 18:34:36 EST

4.1-stable review patch. If anyone has any objections, please let me know.


From: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx>

commit 923a8c1d8069104726bde55c37cec66324ccc328 upstream.

When BT is active, we want to avoid the shared antenna for
management frame to make sure we don't disturb BT. There
was a bug in that code because it chose the antenna
BIT(ANT_A) where ANT_A is already a bitmap (0x1). This
means that the antenna chosen in the end was ANT_B.
While this is not optimal on devices with 2 antennas (it'd
disturb BT), it is critical on single antenna devices like
3160 which couldn't connect at all when BT was active.

This fixes:

Fixes: 34c8b24ff284 ("iwlwifi: mvm: BT Coex - avoid the shared antenna for management frames")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/net/wireless/iwlwifi/mvm/tx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/wireless/iwlwifi/mvm/tx.c
+++ b/drivers/net/wireless/iwlwifi/mvm/tx.c
@@ -225,7 +225,7 @@ void iwl_mvm_set_tx_cmd_rate(struct iwl_

if (info->band == IEEE80211_BAND_2GHZ &&
- rate_flags = BIT(mvm->cfg->non_shared_ant) << RATE_MCS_ANT_POS;
+ rate_flags = mvm->cfg->non_shared_ant << RATE_MCS_ANT_POS;
rate_flags =
BIT(mvm->mgmt_last_antenna_idx) << RATE_MCS_ANT_POS;

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