[mythtv-users] Carbon Footprint

[Roger Siddons]

On Mon, 02 Sep 2013 00:23:19 +0100, Daryl McDonald <darylangela at gmail.com>  
wrote:

> Well I mirrored your settings and scripts and scheduled a recording for  
> 7p.m. gave the system two minutes to shutdown the backend and set >the  
> alarm then powered off, and waited until 7:05p.m. and it did not come  
> on. Does the last line of the following output indicate UTC time?:
> daryl at daryl-A780L3C:~$  sudo grep -i rtc /var/log/dmesg
> [sudo] password for daryl:[    0.199663] RTC time: 19:04:25, date:  
> 09/01/13
> [    1.222545] rtc_cmos 00:03: RTC can wake from S4
> [    1.222673] rtc_cmos 00:03: rtc core: registered rtc_cmos as rtc0
> [    1.222692] rtc0: alarms up to one month, y3k, 114 bytes nvram
> [    1.229942] rtc_cmos 00:03: setting system clock to 2013-09-01  
> 19:04:26 UTC (1378062266)

Yes. On startup the system reads the RTC clock to get the current  
time/date. I suspect it's interpreting the time as UTC (rather than  
localtime) because your file "/etc/default/rcS" contains "UTC=yes". You  
should change that. Type "man /etc/default/rcS" to read more about it.

>
> This is what my disable hwclock script looks like:
> daryl at daryl-A780L3C:~$ cat /etc/init/hwclock-save.conf
> # hwclock-save - save system clock to hardware clock
> # hwclock-save - save system clock to hardware clock
> #
> # This task saves the time from the system clock back to the hardware
> # clock on shutdown.
>
> description	"save system clock to hardware clock"
>
> start on runlevel [06]
>
> task
>
> script
>    . /etc/default/rcS
>    [ "$UTC" = "yes" ] && tz="--utc" || tz="--localtime"
>    [ "$BADYEAR" = "yes" ] && badyear="--badyear"
>    ACPITIME=`cat /proc/acpi/alarm`
>    exec hwclock --rtc=/dev/rtc0 --systohc $tz --noadjfile $badyear
>    echo "$ACPITIME" > /proc/acpi/alarm
> end script
> daryl at daryl-A780L3C:~$

That doesn't look right to me. Up until last year the solution was to  
simply not write the clock. In January someone changed the wiki to  
re-write the alarm after setting the clock but /proc/acpi/alarm is only  
applicable to (old) 2.6 kernels, so it won't have any effect on recent  
kernels (like yours); i.e. hwclock updates aren't being disabled.
However, following Stefan comments, I can confirm that Mythbuntu 12.04  
doesn't need its hwclock disabled so, for you, changing this file is an  
unnecessary distraction and I suggest you put it back to default (delete  
the 2 lines containing ACPITIME) & forget this step.
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