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Commit 48452e5f authored by Mark Lord's avatar Mark Lord Committed by Len Brown
Browse files

/proc/acpi/alarm: handle day-of-month wraparound on readback 



Fix month wrap issue with readback from /proc/acpi/alarm
This bug has been around *forever*.

  $ echo '2008-12-01 10:36:20' > /proc/acpi/alarm
  $ cat /proc/acpi/alarm
  2008-11-01 10:36:20

Note how the readback above shows the month incorrectly
when the alarm is set in the *next* calendar month.
But with this patch applied, it shows the correct month (12).

Signed-off-by: default avatarMark Lord <mlord@pobox.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 437f2f91

drivers/acpi/sleep/proc.c

+32 −21
Original line number Diff line number Diff line
@@ -84,12 +84,15 @@ acpi_system_write_sleep(struct file *file, 
#define	HAVE_ACPI_LEGACY_ALARM

#endif



static u32 cmos_bcd_read(int offset, int rtc_control);



#ifdef	HAVE_ACPI_LEGACY_ALARM



static int acpi_system_alarm_seq_show(struct seq_file *seq, void *offset)

{

	u32 sec, min, hr;

	u32 day, mo, yr, cent = 0;

	u32 today = 0;

	unsigned char rtc_control = 0;

	unsigned long flags;
@@ -97,38 +100,32 @@ static int acpi_system_alarm_seq_show(struct seq_file *seq, void *offset) 


	spin_lock_irqsave(&rtc_lock, flags);



	sec = CMOS_READ(RTC_SECONDS_ALARM);

	min = CMOS_READ(RTC_MINUTES_ALARM);

	hr = CMOS_READ(RTC_HOURS_ALARM);

	rtc_control = CMOS_READ(RTC_CONTROL);

	sec = cmos_bcd_read(RTC_SECONDS_ALARM, rtc_control);

	min = cmos_bcd_read(RTC_MINUTES_ALARM, rtc_control);

	hr = cmos_bcd_read(RTC_HOURS_ALARM, rtc_control);



	/* If we ever get an FACP with proper values... */

	if (acpi_gbl_FADT.day_alarm)

	if (acpi_gbl_FADT.day_alarm) {

		/* ACPI spec: only low 6 its should be cared */

		day = CMOS_READ(acpi_gbl_FADT.day_alarm) & 0x3F;

	else

		day = CMOS_READ(RTC_DAY_OF_MONTH);

		if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)

			day = bcd2bin(day);

	} else

		day = cmos_bcd_read(RTC_DAY_OF_MONTH, rtc_control);

	if (acpi_gbl_FADT.month_alarm)

		mo = CMOS_READ(acpi_gbl_FADT.month_alarm);

	else

		mo = CMOS_READ(RTC_MONTH);

		mo = cmos_bcd_read(acpi_gbl_FADT.month_alarm, rtc_control);

	else {

		mo = cmos_bcd_read(RTC_MONTH, rtc_control);

		today = cmos_bcd_read(RTC_DAY_OF_MONTH, rtc_control);

	}

	if (acpi_gbl_FADT.century)

		cent = CMOS_READ(acpi_gbl_FADT.century);

		cent = cmos_bcd_read(acpi_gbl_FADT.century, rtc_control);



	yr = CMOS_READ(RTC_YEAR);

	yr = cmos_bcd_read(RTC_YEAR, rtc_control);



	spin_unlock_irqrestore(&rtc_lock, flags);



	if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {

		sec = bcd2bin(sec);

		min = bcd2bin(min);

		hr = bcd2bin(hr);

		day = bcd2bin(day);

		mo = bcd2bin(mo);

		yr = bcd2bin(yr);

		cent = bcd2bin(cent);

	}



	/* we're trusting the FADT (see above) */

	if (!acpi_gbl_FADT.century)

		/* If we're not trusting the FADT, we should at least make it
@@ -153,6 +150,20 @@ static int acpi_system_alarm_seq_show(struct seq_file *seq, void *offset) 
	else

		yr += cent * 100;



	/*

	 * Show correct dates for alarms up to a month into the future.

	 * This solves issues for nearly all situations with the common

	 * 30-day alarm clocks in PC hardware.

	 */

	if (day < today) {

		if (mo < 12) {

			mo += 1;

		} else {

			mo = 1;

			yr += 1;

		}

	}



	seq_printf(seq, "%4.4u-", yr);

	(mo > 12) ? seq_puts(seq, "**-") : seq_printf(seq, "%2.2u-", mo);

	(day > 31) ? seq_puts(seq, "** ") : seq_printf(seq, "%2.2u ", day);