[PATCH 6.12 028/567] wifi: rtl8xxxu: Fix HT40 channel config for RTL8192CU, RTL8723AU

Greg Kroah-Hartman
2026-01-06T17:15:50Z

From: Bitterblue Smith <rtl8821cerfe2@gmail.com>

[ Upstream commit 5511ba3de434892e5ef3594d6eabbd12b1629356 ]

Flip the response rate subchannel. It was backwards, causing low
speeds when using 40 MHz channel width. "iw dev ... station dump"
showed a low RX rate, 11M or less.

Also fix the channel width field of RF6052_REG_MODE_AG.

Tested only with RTL8192CU, but these settings are identical for
RTL8723AU.

Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/1f46571d-855b-43e1-8bfc-abacceb96043@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/realtek/rtl8xxxu/core.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtl8xxxu/core.c b/drivers/net/wireless/realtek/rtl8xxxu/core.c
index 260f720550134..b517df2db6d75 100644
--- a/drivers/net/wireless/realtek/rtl8xxxu/core.c
+++ b/drivers/net/wireless/realtek/rtl8xxxu/core.c
@@ -1252,7 +1252,7 @@ void rtl8xxxu_gen1_config_channel(struct ieee80211_hw *hw)
opmode &= ~BW_OPMODE_20MHZ;
rtl8xxxu_write8(priv, REG_BW_OPMODE, opmode);
rsr &= ~RSR_RSC_BANDWIDTH_40M;
- if (sec_ch_above)
+ if (!sec_ch_above)
rsr |= RSR_RSC_UPPER_SUB_CHANNEL;
else
rsr |= RSR_RSC_LOWER_SUB_CHANNEL;
@@ -1321,9 +1321,8 @@ void rtl8xxxu_gen1_config_channel(struct ieee80211_hw *hw)

for (i = RF_A; i < priv->rf_paths; i++) {
val32 = rtl8xxxu_read_rfreg(priv, i, RF6052_REG_MODE_AG);
- if (hw->conf.chandef.width == NL80211_CHAN_WIDTH_40)
- val32 &= ~MODE_AG_CHANNEL_20MHZ;
- else
+ val32 &= ~MODE_AG_BW_MASK;
+ if (hw->conf.chandef.width != NL80211_CHAN_WIDTH_40)
val32 |= MODE_AG_CHANNEL_20MHZ;
rtl8xxxu_write_rfreg(priv, i, RF6052_REG_MODE_AG, val32);
}
--
2.51.0