--- /dev/null
+From ff164ae39b82ee483b24579c8e22a13a8ce5bd04 Mon Sep 17 00:00:00 2001
+From: Riwen Lu <luriwen@kylinos.cn>
+Date: Thu, 6 Jan 2022 16:46:09 +0800
+Subject: rtc: cmos: Evaluate century appropriate
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Riwen Lu <luriwen@kylinos.cn>
+
+commit ff164ae39b82ee483b24579c8e22a13a8ce5bd04 upstream.
+
+There's limiting the year to 2069. When setting the rtc year to 2070,
+reading it returns 1970. Evaluate century starting from 19 to count the
+correct year.
+
+$ sudo date -s 20700106
+Mon 06 Jan 2070 12:00:00 AM CST
+$ sudo hwclock -w
+$ sudo hwclock -r
+1970-01-06 12:00:49.604968+08:00
+
+Fixes: 2a4daadd4d3e5071 ("rtc: cmos: ignore bogus century byte")
+
+Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
+Acked-by: Eric Wong <e@80x24.org>
+Reviewed-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
+Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
+Link: https://lore.kernel.org/r/20220106084609.1223688-1-luriwen@kylinos.cn
+Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl> # preparation for stable
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/rtc/rtc-mc146818-lib.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/drivers/rtc/rtc-mc146818-lib.c
++++ b/drivers/rtc/rtc-mc146818-lib.c
+@@ -82,7 +82,7 @@ unsigned int mc146818_get_time(struct rt
+ time->tm_year += real_year - 72;
+ #endif
+
+- if (century > 20)
++ if (century > 19)
+ time->tm_year += (century - 19) * 100;
+
+ /*