How can I make UPower and the power subsystem recognize that the power supply is plugged in?

My workaround for not charging for helios 500 and manjaro:

Linux XXX 5.2.0-1-MANJARO #1 SMP PREEMPT Sat Jun 22 23:22:07 UTC 2019 x86_64 GNU/Linux

1. Turn on laptop without plugged in AC adapter
2. login
3. Connect AC adapter
4. execute these commands:

echo "manual" > /sys/devices/pci0000:00/0000:00:03.1/0000:06:00.0/0000:07:00.0/0000:08:00.0/power_dpm_force_performance_level

echo 6 > /sys/devices/pci0000:00/0000:00:03.1/0000:06:00.0/0000:07:00.0/0000:08:00.0/pp_dpm_sclk

echo 4 > /sys/devices/pci0000:00/0000:00:03.1/0000:06:00.0/0000:07:00.0/0000:08:00.0/pp_dpm_mclk

After these three commands the charging led start glowing and OS know that the AC adapter is plugged in.

I hope that will help someone.

Based on Pawel Czmock's answer working solution for Ubuntu 18.04 is:

• List available frequencies (pp_dpm_sclk). For that, execute as sudo:

  cd '/sys/devices/pci0000:00'
  DPM_SCLK=$(find . -name 'pp_dpm_sclk')
  echo 'Available SCLK frequencies:'
  cat "$DPM_SCLK"
  

  If you see 1201Mhz there, proceed to next section. If not, you can decide which frequency to use by yourself (based on output from above script) and pass it as argument to script below

• Apply desired frequency setting (by default 1201Mhz or pass argument i.e. 1301Mhz)
  Execute as sudo:

  FREQUENCY="1201Mhz"
  
  if [ -n "$1" ]; then
      FREQUENCY="$1"
  fi
  
  ROOT='/sys/devices/pci0000:00'
  # Set manual level:
  DPM_LEVEL=$(find "$ROOT" -name 'power_dpm_force_performance_level')
  echo "Setting 'manual' level in $DPM_LEVEL"
  echo 'manual' > "$DPM_LEVEL"
  
  # Find frequency selector id:
  DPM_SCLK=$(find "$ROOT" -name 'pp_dpm_sclk')
  SCLK_VALUE=$(grep "$FREQUENCY" "$DPM_SCLK" | cut -d: -f1)
  if [ -z "$SCLK_VALUE" ]; then
      echo "$FREQUENCY not found in $DPM_SCLK"
      exit 1
  fi
  
  # Set frequency
  echo "Setting $FREQUENCY using id $SCLK_VALUE in $DPM_SCLK"
  echo "$SCLK_VALUE" > "$DPM_SCLK"
  
  # pp_dpm_mclk should get set automatically after pp_dpm_sclk is set
  

  After execution of this script CPU, GPU start to work on normal frequencies and Ubuntu switches to 'On-AC' mode as well as power indicator switches on

NOTE: Sometimes the script above executes but does not set those values - Logging out and logging in helps in this situation.

I have the same laptop and the same issue. I have reached out to the ACPI kernel devs but there is no guessing if we will ever have proper ACPI support for our AC power. The "good" news is that I have at least found a work-around to allow us to use the higher perfomance our systems are capable of.

Here are some things to check and try:

• If you boot and your CPU frequencies are stuck at ~500MHz try unplugging the AC adapter. Sometimes it takes more than one attempt. That should kick you on to battery mode power settings. I leave the CPU governor to "ondemand".

• I really recommend amdgpu-utils: https://github.com/Ricks-Lab/amdgpu-utils You will have to add: "amdgpu.ppfeaturemask=0xffff7fff" to your GRUB_CMDLINE_LINUX_DEFAULT= line in your /etc/default/grub and generate the new config, reinstall grub, and then reboot, but once the kernel has that set you now have massive control over your Vega 56. (See we went with AMD for a reason! Yay open-source drivers!)

• The hack I apply to get my GPU up to speed is by setting the P0 state to a higher clock (since it is forced there on "battery mode"). One of the utils is amdgpu-pac and it allows us to edit the P0 state. First, as root, run "amdgpu-pac --execute_pac" and tweak your settings in real time. (The fan will read zero, this is normal as our laptop doesn't use the stock fan.) The power cap is 120w, nothing we can do about that without a hacked BIOS. The 0: Sclk P-State should be changed to a higher Mhz and mV. BE CAREFUL! This is just like overclocking. We have limted amps to go around so we will not be able to just set it to P7: and move on. I tested 1201 Mhz and 875 mV and that seems to work for me. If you find a better combination that's stable let me know. I left Mclk alone except changing "Set Mask:" to "1,2,3" so it cannot use the 0 state. I tried changing the 0: state and it locked everything up. Leave "Power Performance Mode" to AUTO, I noticed no difference changing it. Hitting save will apply it immediately. I use Unigine's heaven benchmark to stress test things (current score: 1761 on extreme"). Once you have settings you like jot them down, restart amdgpu-pac without arguments and set the settings, now when you hit save it will genereate a pac_writer_$$$$$.sh for you to run whenever you want to set the GPU to performance mode. It also helps to generate a reset.sh with the stock settings if you want to go back to saving power. That's about it.

Using these tricks I am able to (mostly) run this laptop at full perfomance under Linux. With any luck the ACPI devs will hear our cries and the future Linux kernels will simply detect our AC apdapter. Good luck!