Windows10 turns the power LED on the Udoo X86 from green to amber when shutdown has completed. That is an apparently useful indication of when it is safe to power-down the board. Unfortunately, Debian Jessie AMD64 behaves differently, and leaves the LED green upon completion of shutdown. Is anyone able to provide a clue about how to pragmatically control the power LED form Debian?
I must confess, I use the 'halt' command to shutdown Debian. That may be the cause of my complaint. https://www.debian.org/releases/stable/amd64/release-notes/ch-information.en.html 5.6.8. systemd: behavior of 'halt' command The sysvinit implementation of the halt command powered off the machine as well. The systemd-sysv implementation halts the system, but does not power off the machine. To halt the machine and turn it off, use the poweroff command. See also Debian bug #760923 https://bugs.debian.org/760923 I'll have to give the 'poweroff' command a try. It would still be useful to know how to access the LED programatically.
I don't think the LEDs can be easily controlled. Warning... Semi-educated stuff below. Ideally, UDOO would answer @LDighera. I'm just poking around schematics and making assumptions. The schematic appears to have LED connected to pins 2,3,4 of the front panel connector. I see things like SATA_LED_N, S5_LED, S3_LED, PLTRST#, BUF_PLTRST#. That last one connects to the SoC, both M.2s, ethernet, LEDs and Arduino headers. An SoC data sheet mentions SATA_LED_N and PMU_PLTRST_N but that's about it. On a side note, what's up with Intel documentation? Used to be that you could get everything about a chip in one document. Now it's spread out and you have to sign up (free?) for access to lots of stuff.
In Debian Stretch, with 'halt' LED stays green but with 'poweroff' or selecting 'shut down' from GUI LED turns amber.
