On Wed, 2016-02-24 at 10:28 +0100, Felix Fietkau wrote: > > + /* > + * HT A-MPDU limits maximum MPDU size to 4095 bytes. Since aggregation > + * sessions are started/stopped without txq flush, use the limit here > + * to avoid having to de-aggregate later. > + */ > + if (skb->len + head->len > 4095 && > + !sta->sta.vht_cap.vht_supported) > + goto out;
I'm not entirely happy with this. You're silently assuming that when VHT is supported, HT MCSes will never be used. This is (I think) true for minstrel_ht, but at the very least you should also document it along with the max_rc_amsdu_len then, which btw I was going to reword to: + * @IEEE80211_HW_TX_AMSDU: Hardware (or driver) supports software aggregated + * A-MSDU frames. Requires software tx queueing and fast-xmit support. + * When not using minstrel/minstrel_ht rate control, the driver needs to + * limit the maximum A-MSDU size based on the current tx rate by setting + * max_rc_amsdu_len in struct ieee80211_sta to avoid mac80211 building + * A-MSDUs that require too much airtime (are too long for a TXOP.) All that said, I'm not sure how much value there really is in aggregating that much? I'd think the value of A-MSDU really is more for lots of small frames like TCP ACKs, since the PER goes up exponentially with the BER for A-MSDU (unlike A-MPDU.) johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
