rtc: cmos: Evaluate century appropriate

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: 2a4daadd4d ("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>
This commit is contained in:
Riwen Lu 2022-01-06 16:46:09 +08:00 committed by Greg Kroah-Hartman
parent 2324f5fcdf
commit 460aa9d873

View File

@ -83,7 +83,7 @@ unsigned int mc146818_get_time(struct rtc_time *time)
time->tm_year += real_year - 72;
#endif
if (century > 20)
if (century > 19)
time->tm_year += (century - 19) * 100;
/*