From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> [ Upstream commit 14705f969d98187a1cc2682e0c9bd2e230b8098f ] On my RTW8821CU chipset rfe_option reads as 0x22. Looking at the vendor driver suggests that the field width of rfe_option is 5 bit, so rfe_option should be masked with 0x1f. Without this the rfe_option comparisons with 2 further down the driver evaluate as false when they should really evaluate as true. The effect is that 2G channels do not work. rfe_option is also used as an array index into rtw8821c_rfe_defs[]. rtw8821c_rfe_defs[34] (0x22) was added as part of adding USB support, likely because rfe_option reads as 0x22. As this now becomes 0x2, rtw8821c_rfe_defs[34] is no longer used and can be removed. Note that this might not be the whole truth. In the vendor driver there are indeed places where the unmasked rfe_option value is used. However, the driver has several places where rfe_option is tested with the pattern if (rfe_option == 2 || rfe_option == 0x22) or if (rfe_option == 4 || rfe_option == 0x24), so that rfe_option BIT(5) has no influence on the code path taken. We therefore mask BIT(5) out from rfe_option entirely until this assumption is proved wrong by some chip variant we do not know yet. Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> Tested-by: Alexandru gagniuc <mr.nuke.me@xxxxxxxxx> Tested-by: Larry Finger <Larry.Finger@xxxxxxxxxxxx> Tested-by: ValdikSS <iam@xxxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Reviewed-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230417140358.2240429-3-s.hauer@xxxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/net/wireless/realtek/rtw88/rtw8821c.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/wireless/realtek/rtw88/rtw8821c.c b/drivers/net/wireless/realtek/rtw88/rtw8821c.c index 9afdc5ce86b43..609a2b86330d8 100644 --- a/drivers/net/wireless/realtek/rtw88/rtw8821c.c +++ b/drivers/net/wireless/realtek/rtw88/rtw8821c.c @@ -41,7 +41,7 @@ static int rtw8821c_read_efuse(struct rtw_dev *rtwdev, u8 *log_map) map = (struct rtw8821c_efuse *)log_map; - efuse->rfe_option = map->rfe_option; + efuse->rfe_option = map->rfe_option & 0x1f; efuse->rf_board_option = map->rf_board_option; efuse->crystal_cap = map->xtal_k; efuse->pa_type_2g = map->pa_type; -- 2.39.2
