Commit 8c99f691 authored Feb 02, 2011 by Rajkumar Manoharan Committed by John W. Linville Feb 04, 2011

mac80211: do not restart ps timer during scan or offchannel



While leaving oper channel, STA informs sleep state to AP to
stop sending data. Till sending ack for the nullfunc, AP
continues to send the data to STA which restarts ps_timer that
is causing unnecessary nullfunc exchange on timer expiry
when the STA was already moved to offchannel. So don't restart ps_timer
on data reception during scan. This issue was identified by
the following warning.

WARNING: at net/mac80211/tx.c:661 invoke_tx_handlers+0xf07/0x1330 [mac80211]
wlan0: Dropped data frame as no usable bitrate found while scanning and
associated. Target station: 00:03:7f:0b:a6:1b on 5 GHz band
Call Trace:
  [<ffffffffa0413ba7>] invoke_tx_handlers+0xf07/0x1330 [mac80211]
  [<ffffffffa0414056>] ieee80211_tx+0x86/0x2c0 [mac80211]
  [<ffffffffa0414345>] ieee80211_xmit+0xb5/0x1d0 [mac80211]
  [<ffffffffa04037e0>] ieee80211_dynamic_ps_enable_work+0x0/0xb0 [mac80211]
  [<ffffffffa04158cf>] ieee80211_tx_skb+0x4f/0x60 [mac80211]
  [<ffffffffa04026e6>] ieee80211_send_nullfunc+0x46/0x60 [mac80211]
  [<ffffffffa0403885>] ieee80211_dynamic_ps_enable_work+0xa5/0xb0 [mac80211]

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

parent 24d24c62

net/mac80211/rx.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -1952,7 +1952,10 @@ ieee80211_rx_h_data(struct ieee80211_rx_data *rx)
		dev->stats.rx_bytes += rx->skb->len;

		if (local->ps_sdata && local->hw.conf.dynamic_ps_timeout > 0 &&
		!is_multicast_ether_addr(((struct ethhdr *)rx->skb->data)->h_dest)) {
		!is_multicast_ether_addr(
		((struct ethhdr *)rx->skb->data)->h_dest) &&
		(!local->scanning &&
		!test_bit(SDATA_STATE_OFFCHANNEL, &sdata->state))) {
		mod_timer(&local->dynamic_ps_timer, jiffies +
		msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
		}

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