The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

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: [PATCH] rtc: cmos: Evaluate century appropriate MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

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

diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c index 7f689f1bafc5..ae9f131b43c0 100644 --- a/drivers/rtc/rtc-mc146818-lib.c +++ b/drivers/rtc/rtc-mc146818-lib.c @@ -159,7 +159,7 @@ int mc146818_get_time(struct rtc_time *time) #endif

#ifdef CONFIG_ACPI - if (p.century > 20) + if (p.century > 19) time->tm_year += (p.century - 19) * 100; #endif