Does ath9k enable the relevant config bit that enforces the TXOP burst
time on transmissions?
ie, bit 12 (TXOP_TBTT_LIMIT_ ENABLE) of 0x8120 (MAC_PCU_MISC_MODE).
FreeBSD doesn't (yet) enable that bit. ath9k doesn't seem to enable
that bit, either in code or in the ar5008/ar9001/ar9002/ar9003
initvals.
What's the hardware doing when that bit isn't enabled? Is it still
enforcing TXOP limits on TXed frames? I've not (yet) seen it do so.
I came across this as a "thing to look at" after I finish off 11n TX,
as I'd like to make sure that both legacy and A-MPDU operation doesn't
exceed burst TXOP. (It's going to be important not only for QOS
compliance, but likely for correct/stable TDMA support.)
Thanks,
Adrian
On 13 August 2011 12:58, Rajkumar Manoharan <rmanohar@xxxxxxxxxxxxxxxx> wrote:
> The WAR which adds extra delimiters when using RTS/CTS
> with aggregation and non-enterprise AR9003 chips.
> This extra padding is done after doing all the 4ms limit
> checks and hence the total aggregate sizes are exceeding
> the allowed duration. This patch limits the aggregate
> sizes appropriately after including these extra delimiters.
>
> Signed-off-by: Rajkumar Manoharan <rmanohar@xxxxxxxxxxxxxxxx>
> ---
> drivers/net/wireless/ath/ath9k/ar9003_mac.c | 28 +-------------------------
> drivers/net/wireless/ath/ath9k/xmit.c | 16 ++++++++++++--
> 2 files changed, 15 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath9k/ar9003_mac.c b/drivers/net/wireless/ath/ath9k/ar9003_mac.c
> index 1aadc47..81ccce1 100644
> --- a/drivers/net/wireless/ath/ath9k/ar9003_mac.c
> +++ b/drivers/net/wireless/ath/ath9k/ar9003_mac.c
> @@ -415,36 +415,12 @@ static void ar9003_hw_set11n_ratescenario(struct ath_hw *ah, void *ds,
> static void ar9003_hw_set11n_aggr_first(struct ath_hw *ah, void *ds,
> u32 aggrLen)
> {
> -#define FIRST_DESC_NDELIMS 60
> struct ar9003_txc *ads = (struct ar9003_txc *) ds;
>
> ads->ctl12 |= (AR_IsAggr | AR_MoreAggr);
>
> - if (ah->ent_mode & AR_ENT_OTP_MPSD) {
> - u32 ctl17, ndelim;
> - /*
> - * Add delimiter when using RTS/CTS with aggregation
> - * and non enterprise AR9003 card
> - */
> - ctl17 = ads->ctl17;
> - ndelim = MS(ctl17, AR_PadDelim);
> -
> - if (ndelim < FIRST_DESC_NDELIMS) {
> - aggrLen += (FIRST_DESC_NDELIMS - ndelim) * 4;
> - ndelim = FIRST_DESC_NDELIMS;
> - }
> -
> - ctl17 &= ~AR_AggrLen;
> - ctl17 |= SM(aggrLen, AR_AggrLen);
> -
> - ctl17 &= ~AR_PadDelim;
> - ctl17 |= SM(ndelim, AR_PadDelim);
> -
> - ads->ctl17 = ctl17;
> - } else {
> - ads->ctl17 &= ~AR_AggrLen;
> - ads->ctl17 |= SM(aggrLen, AR_AggrLen);
> - }
> + ads->ctl17 &= ~AR_AggrLen;
> + ads->ctl17 |= SM(aggrLen, AR_AggrLen);
> }
>
> static void ar9003_hw_set11n_aggr_middle(struct ath_hw *ah, void *ds,
> diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
> index e1d1e90..feef013 100644
> --- a/drivers/net/wireless/ath/ath9k/xmit.c
> +++ b/drivers/net/wireless/ath/ath9k/xmit.c
> @@ -644,8 +644,10 @@ static u32 ath_lookup_rate(struct ath_softc *sc, struct ath_buf *bf,
> * meet the minimum required mpdudensity.
> */
> static int ath_compute_num_delims(struct ath_softc *sc, struct ath_atx_tid *tid,
> - struct ath_buf *bf, u16 frmlen)
> + struct ath_buf *bf, u16 frmlen,
> + bool first_subfrm)
> {
> +#define FIRST_DESC_NDELIMS 60
> struct sk_buff *skb = bf->bf_mpdu;
> struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
> u32 nsymbits, nsymbols;
> @@ -668,6 +670,13 @@ static int ath_compute_num_delims(struct ath_softc *sc, struct ath_atx_tid *tid,
> ndelim += ATH_AGGR_ENCRYPTDELIM;
>
> /*
> + * Add delimiter when using RTS/CTS with aggregation
> + * and non enterprise AR9003 card
> + */
> + if (first_subfrm)
> + ndelim = max(ndelim, FIRST_DESC_NDELIMS);
> +
> + /*
> * Convert desired mpdu density from microeconds to bytes based
> * on highest rate in rate series (i.e. first rate) to determine
> * required minimum length for subframe. Take into account
> @@ -756,7 +765,6 @@ static enum ATH_AGGR_STATUS ath_tx_form_aggr(struct ath_softc *sc,
> status = ATH_AGGR_LIMITED;
> break;
> }
> - nframes++;
>
> /* add padding for previous frame to aggregation length */
> al += bpad + al_delta;
> @@ -765,9 +773,11 @@ static enum ATH_AGGR_STATUS ath_tx_form_aggr(struct ath_softc *sc,
> * Get the delimiters needed to meet the MPDU
> * density for this node.
> */
> - ndelim = ath_compute_num_delims(sc, tid, bf_first, fi->framelen);
> + ndelim = ath_compute_num_delims(sc, tid, bf_first, fi->framelen,
> + !nframes);
> bpad = PADBYTES(al_delta) + (ndelim << 2);
>
> + nframes++;
> bf->bf_next = NULL;
> ath9k_hw_set_desc_link(sc->sc_ah, bf->bf_desc, 0);
>
> --
> 1.7.6
>
> --
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