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Diffstat (limited to 'net/mac80211/scan.c')
-rw-r--r--net/mac80211/scan.c77
1 files changed, 75 insertions, 2 deletions
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 5030a3c87509..3bf9839f5916 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -214,6 +214,66 @@ void ieee80211_scan_failed(struct ieee80211_local *local)
local->scan_req = NULL;
}
+/*
+ * inform AP that we will go to sleep so that it will buffer the frames
+ * while we scan
+ */
+static void ieee80211_scan_ps_enable(struct ieee80211_sub_if_data *sdata)
+{
+ struct ieee80211_local *local = sdata->local;
+ bool ps = false;
+
+ /* FIXME: what to do when local->pspolling is true? */
+
+ del_timer_sync(&local->dynamic_ps_timer);
+ cancel_work_sync(&local->dynamic_ps_enable_work);
+
+ if (local->hw.conf.flags & IEEE80211_CONF_PS) {
+ ps = true;
+ local->hw.conf.flags &= ~IEEE80211_CONF_PS;
+ ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+ }
+
+ if (!ps || !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK))
+ /*
+ * If power save was enabled, no need to send a nullfunc
+ * frame because AP knows that we are sleeping. But if the
+ * hardware is creating the nullfunc frame for power save
+ * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
+ * enabled) and power save was enabled, the firmware just
+ * sent a null frame with power save disabled. So we need
+ * to send a new nullfunc frame to inform the AP that we
+ * are again sleeping.
+ */
+ ieee80211_send_nullfunc(local, sdata, 1);
+}
+
+/* inform AP that we are awake again, unless power save is enabled */
+static void ieee80211_scan_ps_disable(struct ieee80211_sub_if_data *sdata)
+{
+ struct ieee80211_local *local = sdata->local;
+
+ if (!local->powersave)
+ ieee80211_send_nullfunc(local, sdata, 0);
+ else {
+ /*
+ * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
+ * will send a nullfunc frame with the powersave bit set
+ * even though the AP already knows that we are sleeping.
+ * This could be avoided by sending a null frame with power
+ * save bit disabled before enabling the power save, but
+ * this doesn't gain anything.
+ *
+ * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
+ * to send a nullfunc frame because AP already knows that
+ * we are sleeping, let's just enable power save mode in
+ * hardware.
+ */
+ local->hw.conf.flags |= IEEE80211_CONF_PS;
+ ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
+ }
+}
+
void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
{
struct ieee80211_local *local = hw_to_local(hw);
@@ -268,7 +328,7 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
/* Tell AP we're back */
if (sdata->vif.type == NL80211_IFTYPE_STATION) {
if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
- ieee80211_send_nullfunc(local, sdata, 0);
+ ieee80211_scan_ps_disable(sdata);
netif_tx_wake_all_queues(sdata->dev);
}
} else
@@ -409,6 +469,19 @@ int ieee80211_start_scan(struct ieee80211_sub_if_data *scan_sdata,
return 0;
}
+ /*
+ * Hardware/driver doesn't support hw_scan, so use software
+ * scanning instead. First send a nullfunc frame with power save
+ * bit on so that AP will buffer the frames for us while we are not
+ * listening, then send probe requests to each channel and wait for
+ * the responses. After all channels are scanned, tune back to the
+ * original channel and send a nullfunc frame with power save bit
+ * off to trigger the AP to send us all the buffered frames.
+ *
+ * Note that while local->sw_scanning is true everything else but
+ * nullfunc frames and probe requests will be dropped in
+ * ieee80211_tx_h_check_assoc().
+ */
local->sw_scanning = true;
if (local->ops->sw_scan_start)
local->ops->sw_scan_start(local_to_hw(local));
@@ -428,7 +501,7 @@ int ieee80211_start_scan(struct ieee80211_sub_if_data *scan_sdata,
if (sdata->vif.type == NL80211_IFTYPE_STATION) {
if (sdata->u.mgd.flags & IEEE80211_STA_ASSOCIATED) {
netif_tx_stop_all_queues(sdata->dev);
- ieee80211_send_nullfunc(local, sdata, 1);
+ ieee80211_scan_ps_enable(sdata);
}
} else
netif_tx_stop_all_queues(sdata->dev);