This is a note to let you know that I've just added the patch titled
wifi: rtw88: rtw8821c: Fix rfe_option field width
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
wifi-rtw88-rtw8821c-fix-rfe_option-field-width.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8228ea44695e99e6db63c07c111d7d45c8bfc77a
Author: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Date: Mon Apr 17 16:03:56 2023 +0200
wifi: rtw88: rtw8821c: Fix rfe_option field width
[ 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>
diff --git a/drivers/net/wireless/realtek/rtw88/rtw8821c.c b/drivers/net/wireless/realtek/rtw88/rtw8821c.c
index 897da3ed2f029..280602a34fe67 100644
--- a/drivers/net/wireless/realtek/rtw88/rtw8821c.c
+++ b/drivers/net/wireless/realtek/rtw88/rtw8821c.c
@@ -40,7 +40,7 @@ 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;
