mac80211: don't drop nullfunc frames during software scan

[safe/jmp/linux-2.6] / net / mac80211 / scan.c

diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 5030a3c..46f35dc 100644 (file)
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -409,6 +409,19 @@ 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));