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 <vnatarajan@xxxxxxxxxxx>
> ---
> 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);
> + }
> +
There is a comment about the caller waking queues up properly in ath_drain_all_txq(),
I don't think that requirement is handled properly.
Also, mac80211's flush() callback exists precisely for this purpose.
I think it would be better to use that rather than adding a check for every packet.
Sujith
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