On Thu, Feb 3, 2011 at 10:23 PM, Vivek Natarajan <vnatarajan@xxxxxxxxxxx> 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 <vnatarajan@xxxxxxxxxxx>
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
> ---
> Âdrivers/net/wireless/ath/ath9k/xmit.c | Â 10 +++++++++-
> Â1 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,
> Â Â Â Â Â Â Â Â Â Â Â Â Â Âbf->bf_buf_addr,
> Â Â Â Â Â Â Â Â Â Â Â Â Â Âtxq->axq_qnum);
>
> -
> Â Â Â Âreturn bf;
> Â}
>
> @@ -1813,6 +1812,15 @@ int ath_tx_start(struct ieee80211_hw *hw, struct sk_buff *skb,
> Â Â Â Âif (unlikely(!bf))
> Â Â Â Â Â Â Â Âreturn -ENOMEM;
>
> + Â Â Â if (ieee80211_is_nullfunc(hdr->frame_control) &&
> + Â Â Â Â Â ieee80211_has_pm(hdr->frame_control)) {
> + Â Â Â Â Â Â Â /* Drain all the pending frames before we send a nullfunc frame
> + Â Â Â Â Â Â Â Â* to avoid any power save state mismatch between the station
> + Â Â Â Â Â Â Â Â* and the AP.
> + Â Â Â Â Â Â Â Â*/
> + Â Â Â Â Â Â Â ath_drain_all_txq(sc, false);
> + Â Â Â }
> +
> Â Â Â Âq = skb_get_queue_mapping(skb);
> Â Â Â Âspin_lock_bh(&txq->axq_lock);
> Â Â Â Âif (txq == sc->tx.txq_map[q] &&
> --
> 1.6.3.3
>
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