On 03/16/12 13:44, Johannes Berg wrote:
On Fri, 2012-03-16 at 10:26 +0100, Marco Porsch wrote:
Hi all,
in sta_info.c : ieee80211_sta_ps_deliver_response the
IEEE80211_TX_STATUS_EOSP is set for all to-be-sent frames, not only for
the last. But only the last buffered frame actually gets the EOSP flag.
/* set EOSP for the frame */
if (reason == IEEE80211_FRAME_RELEASE_UAPSD&&
qoshdr&& skb_queue_empty(&frames))
*qoshdr |= IEEE80211_QOS_CTL_EOSP;
info->flags |= IEEE80211_TX_STATUS_EOSP |
IEEE80211_TX_CTL_REQ_TX_STATUS;
Consequence is, that the WLAN_STA_SP flag gets cleared (multiple times)
in ieee80211_tx_status before the last frame with EOSP has been sent.
Is this correct?
Looks like the bug is above, the EOSP/TX_STATUS should only be set for
the last frame?
I Agree. But what about the case, when the last frame is not a QoS
frame? Can this even happen - or is U-APSD only for QoS STA?
Then we would have to manually append a QoS Null with the EOSP flag +
TX_STATUS?
So like this:
/* set EOSP for the _last_ frame or appended a QoS Null when needed */
if (reason == IEEE80211_FRAME_RELEASE_UAPSD &&
skb_queue_empty(&frames)) {
if (qoshdr) {
*qoshdr |= IEEE80211_QOS_CTL_EOSP;
info->flags |= IEEE80211_TX_STATUS_EOSP |
IEEE80211_TX_CTL_REQ_TX_STATUS;
} else {
ieee80211_send_null_response(sdata, tid, reason);
}
}
Open issues:
Which tid?
Would this Null now be sent after or before the last frame?
What if the EOSP frame is lost?
Regards,
Marco
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