mac80211: fixup AIFSN instead of disabling WMM (730a7550) · Commits · 戴 / test

Disabling WMM has a huge impact these days. It implies that HT and VHT will be disabled which means that the throughput will be drammatically reduced. Since the AIFSN is a transmission parameter, we can play a bit and fix it up to make it compliant with the 802.11 specification which requires it to be at least 2. Increasing it from 1 to 2 will slightly reduce the likelyhood to get a transmission opportunity compared to other clients that would accept to set AIFSN=1, but at least it will allow HT and VHT which is a huge gain. Signed-off-by:

Emmanuel Grumbach <emmanuel.grumbach@intel.com> Signed-off-by:

Johannes Berg <johannes.berg@intel.com>

net/mac80211/mlme.c

+7 −7

Original line number	Diff line number	Diff line
		@@ -1816,6 +1816,13 @@ static bool ieee80211_sta_wmm_params(struct ieee80211_local *local,
		}

		params.aifs = pos[0] & 0x0f;

		if (params.aifs < 2) {
		sdata_info(sdata,
		"AP has invalid WMM params (AIFSN=%d for ACI %d), will use 2\n",
		params.aifs, aci);
		params.aifs = 2;
		}
		params.cw_max = ecw2cw((pos[1] & 0xf0) >> 4);
		params.cw_min = ecw2cw(pos[1] & 0x0f);
		params.txop = get_unaligned_le16(pos + 2);
		@@ -4559,17 +4566,10 @@ static bool ieee80211_usable_wmm_params(struct ieee80211_sub_if_data *sdata,
		left = len - 8;

		for (; left >= 4; left -= 4, pos += 4) {
		u8 aifsn = pos[0] & 0x0f;
		u8 ecwmin = pos[1] & 0x0f;
		u8 ecwmax = (pos[1] & 0xf0) >> 4;
		int aci = (pos[0] >> 5) & 0x03;

		if (aifsn < 2) {
		sdata_info(sdata,
		"AP has invalid WMM params (AIFSN=%d for ACI %d), disabling WMM\n",
		aifsn, aci);
		return false;
		}
		if (ecwmin > ecwmax) {
		sdata_info(sdata,
		"AP has invalid WMM params (ECWmin/max=%d/%d for ACI %d), disabling WMM\n",

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