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

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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: Mark Lord <mlord@pobox.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Mark Lord 2008-12-09 10:46:30 -05:00 committed by Len Brown
parent 437f2f91d6
commit 48452e5f99
1 changed files with 32 additions and 21 deletions
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53
drivers/acpi/sleep/proc.c
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@ -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);