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    SubjectRe: pm_trace displays the wrong time from the RTC
    On Tue, 31 Jul 2007 17:20:10 -0400 Chuck Ebbert wrote:

    > When resuming, systems print this when booted on 07/31/07:
    >
    > Date: 06/31/107
    >
    > /drivers/base/power/trace.c::read_magic_time():
    > 114 get_rtc_time(&time);
    > 115 printk("Time: %2d:%02d:%02d Date: %02d/%02d/%02d\n",
    > 116 time.tm_hour, time.tm_min, time.tm_sec,
    > 117 time.tm_mon, time.tm_mday, time.tm_year);
    >
    > include/asm-generic/rtc.h:
    > 102 /*
    > 103 * Account for differences between how the RTC uses the values
    > 104 * and how they are defined in a struct rtc_time;
    > 105 */
    > 106 if (time->tm_year <= 69)
    > 107 time->tm_year += 100;
    > 108
    > 109 time->tm_mon--;


    That's this config option (read all of it):

    config PM_TRACE
    bool "Suspend/resume event tracing"
    depends on PM_DEBUG && X86 && EXPERIMENTAL
    default n
    ---help---
    This enables some cheesy code to save the last PM event point in the
    RTC across reboots, so that you can debug a machine that just hangs
    during suspend (or more commonly, during resume).

    To use this debugging feature you should attempt to suspend the machine,
    then reboot it, then run

    dmesg -s 1000000 | grep 'hash matches'

    CAUTION: this option will cause your machine's real-time clock to be
    set to an invalid time after a resume.


    ---
    ~Randy
    *** Remember to use Documentation/SubmitChecklist when testing your code ***
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