mac80211: extend/document powersave API

This modifies hardware flags for powersave to support three different
flags:
 * IEEE80211_HW_SUPPORTS_PS - indicates general PS support
 * IEEE80211_HW_PS_NULLFUNC_STACK - indicates nullfunc sending in software
 * IEEE80211_HW_SUPPORTS_DYNAMIC_PS - indicates dynamic PS on the device

It also adds documentation for all this which explains how to set the
various flags.

Additionally, it fixes a few things:
 * a spot where && was used to test flags
 * enable CONF_PS only when associated again

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/net/wireless/rt2x00/rt73usb.c b/drivers/net/wireless/rt2x00/rt73usb.c
index 2b70c01b55e9..849220236c7d 100644
--- a/drivers/net/wireless/rt2x00/rt73usb.c
+++ b/drivers/net/wireless/rt2x00/rt73usb.c
@@ -2077,7 +2077,9 @@ static int rt73usb_probe_hw_mode(struct rt2x00_dev *rt2x00dev)
          */
         rt2x00dev->hw->flags =
             IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING |
-            IEEE80211_HW_SIGNAL_DBM;
+            IEEE80211_HW_SIGNAL_DBM |
+            IEEE80211_HW_SUPPORTS_PS |
+            IEEE80211_HW_PS_NULLFUNC_STACK;
         rt2x00dev->hw->extra_tx_headroom = TXD_DESC_SIZE;
 
         SET_IEEE80211_DEV(rt2x00dev->hw, rt2x00dev->dev);