mac80211: add U-APSD client support

Add Unscheduled Automatic Power-Save Delivery (U-APSD) client support. The
idea is that the data frames from the client trigger AP to send the buffered
frames with ACs which have U-APSD enabled. This decreases latency and makes it
possible to save even more power.

Driver needs to use IEEE80211_HW_UAPSD to enable the feature. The current
implementation assumes that firmware takes care of the wakeup and
hardware needing IEEE80211_HW_PS_NULLFUNC_STACK is not yet supported.

Tested with wl1251 on a Nokia N900 and Cisco Aironet 1231G AP and running
various test traffic with ping.

Signed-off-by: Kalle Valo <kalle.valo@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 468829143991..0054bba08ce1 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -491,6 +491,10 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
         else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC)
                 local->hw.wiphy->signal_type = CFG80211_SIGNAL_TYPE_UNSPEC;
 
+        WARN((local->hw.flags & IEEE80211_HW_SUPPORTS_UAPSD)
+             && (local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK),
+             "U-APSD not supported with HW_PS_NULLFUNC_STACK\n");
+
         /*
          * Calculate scan IE length -- we need this to alloc
          * memory and to subtract from the driver limit. It