From: Greg KH on
2.6.32-stable review patch. If anyone has any objections, please let us know.

------------------

From: Vivek Natarajan <vnatarajan(a)atheros.com>

commit e15276a4b220c54db665cf46a92bd9ceb9aeb052 upstream.

The current mac80211 implementation enables power save if there
is no Tx traffic for a specific timeout. Hence, PS is triggered
even if there is a continuous Rx only traffic(like UDP) going on.
This makes the drivers to wait on the tim bit in the next beacon
to awake which leads to redundant sleep-wake cycles.
Fix this by restarting the dynamic ps timer on receiving every
data packet.

Signed-off-by: Vivek Natarajan <vnatarajan(a)atheros.com>
Signed-off-by: John W. Linville <linville(a)tuxdriver.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez(a)atheros.com>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de>

---
net/mac80211/rx.c | 8 ++++++++
1 file changed, 8 insertions(+)

--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1590,6 +1590,7 @@ static ieee80211_rx_result debug_noinlin
ieee80211_rx_h_data(struct ieee80211_rx_data *rx)
{
struct net_device *dev = rx->dev;
+ struct ieee80211_local *local = rx->local;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
__le16 fc = hdr->frame_control;
int err;
@@ -1612,6 +1613,13 @@ ieee80211_rx_h_data(struct ieee80211_rx_
dev->stats.rx_packets++;
dev->stats.rx_bytes += rx->skb->len;

+ if (ieee80211_is_data(hdr->frame_control) &&
+ !is_multicast_ether_addr(hdr->addr1) &&
+ local->hw.conf.dynamic_ps_timeout > 0 && local->ps_sdata) {
+ mod_timer(&local->dynamic_ps_timer, jiffies +
+ msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
+ }
+
ieee80211_deliver_skb(rx);

return RX_QUEUED;


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