--- zzzz-none-000/linux-3.10.107/include/asm-generic/rtc.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/include/asm-generic/rtc.h	2021-02-04 17:41:59.000000000 +0000
@@ -16,6 +16,9 @@
 #include <linux/rtc.h>
 #include <linux/bcd.h>
 #include <linux/delay.h>
+#ifdef CONFIG_ACPI
+#include <linux/acpi.h>
+#endif
 
 #define RTC_PIE 0x40		/* periodic interrupt enable */
 #define RTC_AIE 0x20		/* alarm interrupt enable */
@@ -46,6 +49,7 @@
 {
 	unsigned char ctrl;
 	unsigned long flags;
+	unsigned char century = 0;
 
 #ifdef CONFIG_MACH_DECSTATION
 	unsigned int real_year;
@@ -79,6 +83,11 @@
 #ifdef CONFIG_MACH_DECSTATION
 	real_year = CMOS_READ(RTC_DEC_YEAR);
 #endif
+#ifdef CONFIG_ACPI
+	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
+	    acpi_gbl_FADT.century)
+		century = CMOS_READ(acpi_gbl_FADT.century);
+#endif
 	ctrl = CMOS_READ(RTC_CONTROL);
 	spin_unlock_irqrestore(&rtc_lock, flags);
 
@@ -90,12 +99,16 @@
 		time->tm_mday = bcd2bin(time->tm_mday);
 		time->tm_mon = bcd2bin(time->tm_mon);
 		time->tm_year = bcd2bin(time->tm_year);
+		century = bcd2bin(century);
 	}
 
 #ifdef CONFIG_MACH_DECSTATION
 	time->tm_year += real_year - 72;
 #endif
 
+	if (century)
+		time->tm_year += (century - 19) * 100;
+
 	/*
 	 * Account for differences between how the RTC uses the values
 	 * and how they are defined in a struct rtc_time;
@@ -122,6 +135,7 @@
 #ifdef CONFIG_MACH_DECSTATION
 	unsigned int real_yrs, leap_yr;
 #endif
+	unsigned char century = 0;
 
 	yrs = time->tm_year;
 	mon = time->tm_mon + 1;   /* tm_mon starts at zero */
@@ -150,6 +164,15 @@
 		yrs = 73;
 	}
 #endif
+
+#ifdef CONFIG_ACPI
+	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
+	    acpi_gbl_FADT.century) {
+		century = (yrs + 1900) / 100;
+		yrs %= 100;
+	}
+#endif
+
 	/* These limits and adjustments are independent of
 	 * whether the chip is in binary mode or not.
 	 */
@@ -169,6 +192,7 @@
 		day = bin2bcd(day);
 		mon = bin2bcd(mon);
 		yrs = bin2bcd(yrs);
+		century = bin2bcd(century);
 	}
 
 	save_control = CMOS_READ(RTC_CONTROL);
@@ -185,6 +209,11 @@
 	CMOS_WRITE(hrs, RTC_HOURS);
 	CMOS_WRITE(min, RTC_MINUTES);
 	CMOS_WRITE(sec, RTC_SECONDS);
+#ifdef CONFIG_ACPI
+	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
+	    acpi_gbl_FADT.century)
+		CMOS_WRITE(century, acpi_gbl_FADT.century);
+#endif
 
 	CMOS_WRITE(save_control, RTC_CONTROL);
 	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);