Return-path: Received: from mail-iw0-f174.google.com ([209.85.214.174]:64881 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751582Ab1BDHgV convert rfc822-to-8bit (ORCPT ); Fri, 4 Feb 2011 02:36:21 -0500 Received: by iwn9 with SMTP id 9so1888439iwn.19 for ; Thu, 03 Feb 2011 23:36:21 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1296800640-6381-1-git-send-email-vnatarajan@atheros.com> References: <1296800640-6381-1-git-send-email-vnatarajan@atheros.com> From: "Luis R. Rodriguez" Date: Thu, 3 Feb 2011 23:36:01 -0800 Message-ID: Subject: Re: [PATCH 1/2] ath9k: Drain txq before sending a nullfunc frame. To: Vivek Natarajan Cc: linville@tuxdriver.com, linux-wireless@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, Feb 3, 2011 at 10:23 PM, Vivek Natarajan wrote: > In a highly noisy environment, a data frame which is queued before > a nullfunc frame on a different hw queue may be sent over the air > after the tx completion of nullfunc frame. This causes the station > to enter power save and the AP to see the station as awake and > continues to send the data traffic. Fix this by draining all tx > queues before we send the null function frame with PM bit set. > > Signed-off-by: Vivek Natarajan Hm nice, this is a good example of one of those random not-so-critical but still nice fixes which I wish would go to stable. John, Greg, any qualms for such things to go to stable if they apply? It was my impression we could send it, but I want to verify with both you guys so neither we or John get bashed if we try to send it as a stable fix. Vivek, is this applicable to stable kernels or does the hunk not even apply? Luis > --- >  drivers/net/wireless/ath/ath9k/xmit.c |   10 +++++++++- >  1 files changed, 9 insertions(+), 1 deletions(-) > > diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c > index 68a1c76..0cb6017 100644 > --- a/drivers/net/wireless/ath/ath9k/xmit.c > +++ b/drivers/net/wireless/ath/ath9k/xmit.c > @@ -1710,7 +1710,6 @@ static struct ath_buf *ath_tx_setup_buffer(struct ieee80211_hw *hw, >                            bf->bf_buf_addr, >                            txq->axq_qnum); > > - >        return bf; >  } > > @@ -1813,6 +1812,15 @@ int ath_tx_start(struct ieee80211_hw *hw, struct sk_buff *skb, >        if (unlikely(!bf)) >                return -ENOMEM; > > +       if (ieee80211_is_nullfunc(hdr->frame_control) && > +           ieee80211_has_pm(hdr->frame_control)) { > +               /* Drain all the pending frames before we send a nullfunc frame > +                * to avoid any power save state mismatch between the station > +                * and the AP. > +                */ > +               ath_drain_all_txq(sc, false); > +       } > + >        q = skb_get_queue_mapping(skb); >        spin_lock_bh(&txq->axq_lock); >        if (txq == sc->tx.txq_map[q] && > -- > 1.6.3.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-wireless" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at  http://vger.kernel.org/majordomo-info.html >