From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> commit 14705f969d98187a1cc2682e0c9bd2e230b8098f upstream. 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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/realtek/rtw88/rtw8821c.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/net/wireless/realtek/rtw88/rtw8821c.c +++ b/drivers/net/wireless/realtek/rtw88/rtw8821c.c @@ -47,7 +47,7 @@ static int rtw8821c_read_efuse(struct rt 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; @@ -1537,7 +1537,6 @@ static const struct rtw_rfe_def rtw8821c [2] = RTW_DEF_RFE_EXT(8821c, 0, 0, 2), [4] = RTW_DEF_RFE_EXT(8821c, 0, 0, 2), [6] = RTW_DEF_RFE(8821c, 0, 0), - [34] = RTW_DEF_RFE(8821c, 0, 0), }; static struct rtw_hw_reg rtw8821c_dig[] = {
