iwlwifi: mvm: Disable uAPSD for a DCM client

A binding object associates virtual MACs to a Phy.
Binding object can ask (and get) air time, thus
allowing several MACs to share the medium.
A binding object can be in either one of 3 states:
1) standalone - A single active MAC
2) Different Channel Mode (DCM) - There are 2 active
   MACs or more (not necessarily just clients), but each
   has its own channel.
3) Same Channel Mode (SCM) - There are 2 active
   MACs or more (not necessarily just clients), that
   share the same channel.
This patch introduces an additional condition for enabling uAPSD:
uAPSD should be disabled for a client in DCM.
The reason for that is a low latency issue in Miracast.

Signed-off-by: Avri Altman <avri.altman@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

diff --git a/drivers/net/wireless/iwlwifi/mvm/power.c b/drivers/net/wireless/iwlwifi/mvm/power.c
index 258405f..9985273 100644 (file)
--- a/drivers/net/wireless/iwlwifi/mvm/power.c
+++ b/drivers/net/wireless/iwlwifi/mvm/power.c
@@ -268,10 +268,30 @@ static void iwl_mvm_power_configure_uapsd(struct iwl_mvm *mvm,
                IWL_MVM_PS_HEAVY_RX_THLD_PERCENT;
 }
 
+static void iwl_mvm_binding_iterator(void *_data, u8 *mac,
+                                     struct ieee80211_vif *vif)
+{
+       unsigned long *data = _data;
+       struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+
+       if (!mvmvif->phy_ctxt)
+               return;
+
+       if (vif->type == NL80211_IFTYPE_STATION ||
+           vif->type == NL80211_IFTYPE_AP)
+               __set_bit(mvmvif->phy_ctxt->id, data);
+}
+
 static bool iwl_mvm_power_allow_uapsd(struct iwl_mvm *mvm,
                                       struct ieee80211_vif *vif)
 {
        struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+       unsigned long phy_ctxt_counter = 0;
+
+       ieee80211_iterate_active_interfaces_atomic(mvm->hw,
+                                                  IEEE80211_IFACE_ITER_NORMAL,
+                                                  iwl_mvm_binding_iterator,
+                                                  &phy_ctxt_counter);
 
        if (!memcmp(mvmvif->uapsd_misbehaving_bssid, vif->bss_conf.bssid,
                    ETH_ALEN))
@@ -289,6 +309,13 @@ static bool iwl_mvm_power_allow_uapsd(struct iwl_mvm *mvm,
            IEEE80211_P2P_OPPPS_ENABLE_BIT))
                return false;
 
+       /*
+        * Avoid using uAPSD if client is in DCM -
+        * low latency issue in Miracast
+        */
+       if (hweight8(phy_ctxt_counter) >= 2)
+               return false;
+
        return true;
 }