We observe unexpected connection drops with some APs due to
non-acked mac80211 generated null data frames (keep-alive).
After debugging and capture, we noticed that null frames are
submitted at standard data bitrate and that the given APs are
in trouble with that.
After setting the null frame bitrate to control bitrate, all
null frames are acked as expected and connection is maintained.
Not sure if it's a requirement of the specification, but it seems
the right thing to do anyway, null frames are mostly used for control
purpose (power-saving, keep-alive...), and submitting them with
a slower/simpler bitrate/modulation is more robust.
Cc: [email protected]
Fixes: 512b191d9652 ("wcn36xx: Fix TX data path")
Signed-off-by: Loic Poulain <[email protected]>
---
drivers/net/wireless/ath/wcn36xx/txrx.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/net/wireless/ath/wcn36xx/txrx.c b/drivers/net/wireless/ath/wcn36xx/txrx.c
index ef1b133..ce4f631 100644
--- a/drivers/net/wireless/ath/wcn36xx/txrx.c
+++ b/drivers/net/wireless/ath/wcn36xx/txrx.c
@@ -535,6 +535,7 @@ static void wcn36xx_set_tx_data(struct wcn36xx_tx_bd *bd,
if (ieee80211_is_any_nullfunc(hdr->frame_control)) {
/* Don't use a regular queue for null packet (no ampdu) */
bd->queue_id = WCN36XX_TX_U_WQ_ID;
+ bd->bd_rate = WCN36XX_BD_RATE_CTRL;
}
if (bcast) {
--
2.7.4
Loic Poulain <[email protected]> wrote:
> We observe unexpected connection drops with some APs due to
> non-acked mac80211 generated null data frames (keep-alive).
> After debugging and capture, we noticed that null frames are
> submitted at standard data bitrate and that the given APs are
> in trouble with that.
>
> After setting the null frame bitrate to control bitrate, all
> null frames are acked as expected and connection is maintained.
>
> Not sure if it's a requirement of the specification, but it seems
> the right thing to do anyway, null frames are mostly used for control
> purpose (power-saving, keep-alive...), and submitting them with
> a slower/simpler bitrate/modulation is more robust.
>
> Cc: [email protected]
> Fixes: 512b191d9652 ("wcn36xx: Fix TX data path")
> Signed-off-by: Loic Poulain <[email protected]>
> Signed-off-by: Kalle Valo <[email protected]>
Patch applied to ath-next branch of ath.git, thanks.
d3fd2c95c1c1 wcn36xx: Fix (QoS) null data frame bitrate/modulation
--
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches