Linux USB: turning the power on and off?

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遥遥无期
遥遥无期 2020-12-07 10:41

How can I programmatically enable and disable the power to a particular USB port on Linux? Is such a thing even possible? Mac answers appreciated as well!

I was tryi

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  •  日久生厌
    2020-12-07 10:54

    There is a sys entry for this in Linux. From Documentation/usb/power-management.txt:

    power/level

    This file contains one of three words: "on", "auto",
    or "suspend".  You can write those words to the file
    to change the device's setting.
    
    "on" means that the device should be resumed and
    autosuspend is not allowed.  (Of course, system
    suspends are still allowed.)
    
    "auto" is the normal state in which the kernel is
    allowed to autosuspend and autoresume the device.
    
    "suspend" means that the device should remain
    suspended, and autoresume is not allowed.  (But remote
    wakeup may still be allowed, since it is controlled
    separately by the power/wakeup attribute.)
    

    Something like: echo on > /sys/bus/usb/devices/usb5/power/level

    You may need to play with the autosuspend setting as well. Without telling the kernel to stop trying, it may suspend the port automatically.

    Good luck!

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