On Fri, Apr 09, 2021 at 10:23:10PM -0400, Stewart C. Russell via talk wrote:
This may be old news to many of you, but today I learned you can have the computer's real time clock boot your machine at a specific time. The more proper way seems to be to use the 'rtcwake' command, but you can also do it by writing the timestamp of the startup time to /sys/class/rtc/rtc0/wakealarm
Some more details of the /sys method - https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=309093&p=1849326&sid=ca7a14f7d160f929378be4691b1aed9e#p1849291
Yes many PCs have had an option for the RTC to turn on the machine (could even configure it in the BIOS to always turn on the computer at a certain time for you). I have never used it (I don't tend to turn the computer off in the first place). No idea how many other platforms support it although I suspect not very many. I didn't think the raspberry pi even had a concept of software power control, which would make the RTC doing anything rather unlikely, although if it is just sleeping that would be a different story. Although suspend and sleep have often been rather hit or miss in my experience. -- Len Sorensen