[3.19.y-ckt stable] Patch "iwlwifi: mvm: fix antenna selection when BT is active" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    iwlwifi: mvm: fix antenna selection when BT is active

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt6.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From fd4ec67d28e83dedbbe301a1d675b2067c237c10 Mon Sep 17 00:00:00 2001
From: Emmanuel Grumbach <emmanuel.grumbach at intel.com>
Date: Sun, 31 May 2015 21:44:22 +0300
Subject: iwlwifi: mvm: fix antenna selection when BT is active

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:
https://bugzilla.kernel.org/show_bug.cgi?id=97181

Fixes: 34c8b24ff284 ("iwlwifi: mvm: BT Coex - avoid the shared antenna for management frames")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach at intel.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/wireless/iwlwifi/mvm/tx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/iwlwifi/mvm/tx.c b/drivers/net/wireless/iwlwifi/mvm/tx.c
index 650a5f0..ac12bc5 100644
--- 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_mvm *mvm, struct iwl_tx_cmd *tx_cmd,

 	if (info->band == IEEE80211_BAND_2GHZ &&
 	    !iwl_mvm_bt_coex_is_shared_ant_avail(mvm))
-		rate_flags = BIT(mvm->cfg->non_shared_ant) << RATE_MCS_ANT_POS;
+		rate_flags = mvm->cfg->non_shared_ant << RATE_MCS_ANT_POS;
 	else
 		rate_flags =
 			BIT(mvm->mgmt_last_antenna_idx) << RATE_MCS_ANT_POS;
--
1.9.1