From: Eric Wong e@80x24.org
[ Upstream commit 2a4daadd4d3e507138f8937926e6a4df49c6bfdc ]
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: 3c217e51d8a272b9 ("rtc: cmos: century support")
Cc: Alexandre Belloni alexandre.belloni@bootlin.com Cc: Alessandro Zummo a.zummo@towertech.it Cc: Sylvain Chouleur sylvain.chouleur@intel.com Cc: Patrick McDermott patrick.mcdermott@libiquity.com Cc: linux-rtc@vger.kernel.org Signed-off-by: Eric Wong e@80x24.org Signed-off-by: Alexandre Belloni alexandre.belloni@bootlin.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/rtc/rtc-mc146818-lib.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c index 2f1772a..18a6f15 100644 --- a/drivers/rtc/rtc-mc146818-lib.c +++ b/drivers/rtc/rtc-mc146818-lib.c @@ -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;
/*