6.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Benjamin Berg benjamin.berg@intel.com
commit 75575e2d252afb29fdbcbeec4d67e042007add52 upstream.
The EHT PHY requirements state that 80 MHz must be supported on the 5 and 6 GHz bands unless the STA is 20 MHz only. So if the channel width is limited to 40 MHz on a band other than 2.4 GHz, then disable EHT and downgrade to HE.
The primary case where this can happen is if the hardware disables puncturing using IEEE80211_HW_DISALLOW_PUNCTURING.
Signed-off-by: Benjamin Berg benjamin.berg@intel.com Cc: stable@vger.kernel.org Reviewed-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Miri Korenblit miriam.rachel.korenblit@intel.com Link: https://patch.msgid.link/20250826202553.a6582f3abf57.Ic670429dc7127f68c818b4... Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mac80211/mlme.c | 8 ++++++++ net/mac80211/tests/chan-mode.c | 30 +++++++++++++++++++++++++----- 2 files changed, 33 insertions(+), 5 deletions(-)
--- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -1193,6 +1193,14 @@ again: "required MCSes not supported, disabling EHT\n"); }
+ if (conn->mode >= IEEE80211_CONN_MODE_EHT && + channel->band != NL80211_BAND_2GHZ && + conn->bw_limit == IEEE80211_CONN_BW_LIMIT_40) { + conn->mode = IEEE80211_CONN_MODE_HE; + link_id_info(sdata, link_id, + "required bandwidth not supported, disabling EHT\n"); + } + /* the mode can only decrease, so this must terminate */ if (ap_mode != conn->mode) { kfree(elems); --- a/net/mac80211/tests/chan-mode.c +++ b/net/mac80211/tests/chan-mode.c @@ -2,7 +2,7 @@ /* * KUnit tests for channel mode functions * - * Copyright (C) 2024 Intel Corporation + * Copyright (C) 2024-2025 Intel Corporation */ #include <net/cfg80211.h> #include <kunit/test.h> @@ -28,6 +28,10 @@ static const struct determine_chan_mode_ u8 vht_basic_mcs_1_4, vht_basic_mcs_5_8; u8 he_basic_mcs_1_4, he_basic_mcs_5_8; u8 eht_mcs7_min_nss; + u16 eht_disabled_subchannels; + u8 eht_bw; + enum ieee80211_conn_bw_limit conn_bw_limit; + enum ieee80211_conn_bw_limit expected_bw_limit; int error; } determine_chan_mode_cases[] = { { @@ -128,6 +132,14 @@ static const struct determine_chan_mode_ .conn_mode = IEEE80211_CONN_MODE_EHT, .eht_mcs7_min_nss = 0x15, .error = EINVAL, + }, { + .desc = "80 MHz EHT is downgraded to 40 MHz HE due to puncturing", + .conn_mode = IEEE80211_CONN_MODE_EHT, + .expected_mode = IEEE80211_CONN_MODE_HE, + .conn_bw_limit = IEEE80211_CONN_BW_LIMIT_80, + .expected_bw_limit = IEEE80211_CONN_BW_LIMIT_40, + .eht_disabled_subchannels = 0x08, + .eht_bw = IEEE80211_EHT_OPER_CHAN_WIDTH_80MHZ, } }; KUNIT_ARRAY_PARAM_DESC(determine_chan_mode, determine_chan_mode_cases, desc) @@ -138,7 +150,7 @@ static void test_determine_chan_mode(str struct t_sdata *t_sdata = T_SDATA(test); struct ieee80211_conn_settings conn = { .mode = params->conn_mode, - .bw_limit = IEEE80211_CONN_BW_LIMIT_20, + .bw_limit = params->conn_bw_limit, }; struct cfg80211_bss cbss = { .channel = &t_sdata->band_5ghz.channels[0], @@ -191,14 +203,21 @@ static void test_determine_chan_mode(str 0x7f, 0x01, 0x00, 0x88, 0x88, 0x88, 0x00, 0x00, 0x00, /* EHT Operation */ - WLAN_EID_EXTENSION, 0x09, WLAN_EID_EXT_EHT_OPERATION, - 0x01, params->eht_mcs7_min_nss ? params->eht_mcs7_min_nss : 0x11, - 0x00, 0x00, 0x00, 0x00, 0x24, 0x00, + WLAN_EID_EXTENSION, 0x0b, WLAN_EID_EXT_EHT_OPERATION, + 0x03, params->eht_mcs7_min_nss ? params->eht_mcs7_min_nss : 0x11, + 0x00, 0x00, 0x00, params->eht_bw, + params->eht_bw == IEEE80211_EHT_OPER_CHAN_WIDTH_80MHZ ? 42 : 36, + 0x00, + u16_get_bits(params->eht_disabled_subchannels, 0xff), + u16_get_bits(params->eht_disabled_subchannels, 0xff00), }; struct ieee80211_chan_req chanreq = {}; struct cfg80211_chan_def ap_chandef = {}; struct ieee802_11_elems *elems;
+ /* To force EHT downgrade to HE on punctured 80 MHz downgraded to 40 MHz */ + set_bit(IEEE80211_HW_DISALLOW_PUNCTURING, t_sdata->local.hw.flags); + if (params->strict) set_bit(IEEE80211_HW_STRICT, t_sdata->local.hw.flags); else @@ -237,6 +256,7 @@ static void test_determine_chan_mode(str } else { KUNIT_ASSERT_NOT_ERR_OR_NULL(test, elems); KUNIT_ASSERT_EQ(test, conn.mode, params->expected_mode); + KUNIT_ASSERT_EQ(test, conn.bw_limit, params->expected_bw_limit); } }