rtc: cmos: ignore bogus century byte

Older versions of Libreboot and Coreboot had an invalid value
(`3' in my case) in the century byte affecting the GM45 in
the Thinkpad X200.  Not everybody's updated their firmwares,
and Linux <= 4.2 was able to read the RTC without problems,
so workaround this by ignoring invalid values.

Fixes: 3c217e51d8 ("rtc: cmos: century support")

Cc: Alexandre Belloni <[email protected]>
Cc: Alessandro Zummo <[email protected]>
Cc: Sylvain Chouleur <[email protected]>
Cc: Patrick McDermott <[email protected]>
Cc: [email protected]
Signed-off-by: Eric Wong <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>
This commit is contained in:
Eric Wong 2019-01-06 08:21:03 +00:00 • committed by Alexandre Belloni
commit 2a4daadd4d

View file

@ -82,7 +82,7 @@ unsigned int mc146818_get_time(struct rtc_time *time)
time->tm_year += real_year - 72;
#endif
if (century)
if (century > 20)
time->tm_year += (century - 19) * 100;
/*