Power LED Indications and Control

Discussion in 'UDOO X86' started by LDighera, Apr 27, 2017.

  1. LDighera

    LDighera UDOOer

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    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?
     
  2. LDighera

    LDighera UDOOer

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    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.
     
  3. Brad

    Brad New Member

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    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.
     
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  4. Markus Laire

    Markus Laire Active Member

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    In Debian Stretch, with 'halt' LED stays green but with 'poweroff' or selecting 'shut down' from GUI LED turns amber.
     

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