Just remembered, and maybe somebody finds this useful:
one can also wake board with on-chip RTC:
- patch the kernel with http://patchwork.ozlabs.org/linuxppc-em ... h?id=11675
and use some util to set alarm on /dev/rtc0 (but don't close the file, that disabled the alarm IIRC)
- use something like devmem2 to set RTC alarm registers
Well, at least in theory. I've only tested RTC alarm wakeups on another mpc5200b board, and it was months ago.
It works :)
The problem with the internal RTC is it has no voltage to it when the system is turned off. The 5200B basically forgets the time when you really shut down.
So, it's only useful in Standby (i.e. tell it to standby and then wakeup, rather tell it to turn off but turn back on). You may not save as much power this way. USB peripherals are still powered, the disk might still be turned on, lots of other niggles you have to manually tweak for the standby process.
The RTC replacement we have on the Efika (actually a small 8-bit PIC) will wake the system up from shutdown (i.e. hard power off), though, I believe there is a cute way of doing this from inside Linux, and RTAS..
Matt Sealey, Genesi USA Inc.
Product Development Analyst