wifi: rtw89: disable CSI STBC for VHT 160MHz

Fix interoperability problem where CSI feedback with STBC enabled at
VHT 160MHz BW cannot be properly decoded by certain APs, causing CSI
reports to be rejected. This problem is specific to Wi-Fi 7 chips,
as Wi-Fi 6 defaults to 20MHz CSI BW. Therefore, disable STBC encoding
for CSI transmission in VHT 160MHz mode to ensure CSI feedback is
accepted by these APs and maintain smooth throughput.

Signed-off-by: Dian-Syuan Yang <dian_syuan0116@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20260424072552.59220-4-pkshih@realtek.com

diff --git a/drivers/net/wireless/realtek/rtw89/mac_be.c b/drivers/net/wireless/realtek/rtw89/mac_be.c
index a0fa8e0597398730707306779efbce8f365a041e..dd0dbe78a1ed1e76f4711b8cef354ebfeda627f1 100644 (file)
--- a/drivers/net/wireless/realtek/rtw89/mac_be.c
+++ b/drivers/net/wireless/realtek/rtw89/mac_be.c
@@ -2805,6 +2805,10 @@ static int rtw89_mac_set_csi_para_reg_be(struct rtw89_dev *rtwdev,
                sound_dim = min(sound_dim, t);
        }
 
+       /* Disable stbc_en in VHT 160MHz to avoid IOT issues with certain APs */
+       if (link_sta->vht_cap.cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ)
+               stbc_en = 0;
+
        nc = min(nc, sound_dim);
        nr = min(nr, sound_dim);