Prevent unwanted wake up for ThinkPad X280 running Ubuntu 18.04 (bionic)

There is an issue that X280 may wake up while it’s connected to the ThinkPad USB-C hub. Here is the workaround for this issue.

Scripts under /lib/systemd/system-sleep directory will be executed before and after suspend. Thus we can put a script /lib/systemd/system-sleep and manipulate /proc/acpi/wakeup and /sys/bus/usb/devices/*/power/wakeup before suspend.

sudo touch /lib/systemd/system-sleep/prevent-unwanted-wakeup
sudo chmod +x /lib/systemd/system-sleep/prevent-unwanted-wakeup

Edit /lib/systemd/system-sleep/prevent-unwanted-wakeup

#!/usr/bin/env ruby
# encoding: utf-8

def disable_acpi_wakeup(only_on_arr = nil)
  arr_to_disable = []

  File.open("/proc/acpi/wakeup", "rb"){|file|
    content = file.read()
    content.each_line{|line|
      line.chomp!
      arr = line.gsub("\t", " ").split(" ")
      if arr[2] == "*enabled"
        arr_to_disable.push(arr[0])
      end
    }
  }

  if only_on_arr != nil
    arr_to_disable = arr_to_disable & only_on_arr
  end

  arr_to_disable.each{|item|
    File.open("/proc/acpi/wakeup", "wb"){|file|
      file.write(item)
    }
  }
end


def disable_usb_wakeup(node = "*")
  arr_to_disable = []
  Dir.glob("/sys/bus/usb/devices/#{node}/power/wakeup"){|path|
    
    File.open(path, "rb"){|file|
      content = file.read()
      content.chomp!
      if content == "enabled"
        arr_to_disable.push(path)
      end
    }
  }
  arr_to_disable.each{|item|
    File.open(item, "wb"){|file|
      file.write("disabled")
    }
  }
end

if ARGV[0] == "pre" && ARGV[1] == "suspend"
#  disable_acpi_wakeup()         # Disable all wakeup type in /proc/acpi/wakeup
  disable_acpi_wakeup(["XHC"])  # Disable USB wakeup
#  disable_usb_wakeup("1-7")     # Disable wakeup from Bluetooth (a USB device)
elsif ARGV[0] == "post" && ARGV[1] == "suspend"
end

Ubuntu will run

•  /lib/systemd/system-sleep/prevent-unwanted-wakeup pre suspend before entering suspend mode
•  /lib/systemd/system-sleep/prevent-unwanted-wakeup post suspend after wakeup