From 48452e5f99ab35d643df0463b6ad11aea8ea7bdc Mon Sep 17 00:00:00 2001 From: Mark Lord <lkml@rtr.ca> Date: Tue, 9 Dec 2008 10:46:30 -0500 Subject: [PATCH] /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: Mark Lord <mlord@pobox.com> Signed-off-by: Len Brown <len.brown@intel.com> --- drivers/acpi/sleep/proc.c | 53 +++++++++++++++++++++++---------------- 1 file changed, 32 insertions(+), 21 deletions(-) diff --git a/drivers/acpi/sleep/proc.c b/drivers/acpi/sleep/proc.c index 4dbc2271acf5..232d4b64140b 100644 --- a/drivers/acpi/sleep/proc.c +++ b/drivers/acpi/sleep/proc.c @@ -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);