Power estimation of USB-C adapter higher than discharge rate

[paulmenzel]

On a Dell XPS 13 9360 with Debian sid/unstable and powertop 2.15-1, the energy consumption of a connected Dell DA300 USB-C adapter is shown to draw more power the shown discharge rate:

The battery reports a discharge rate of 6.14 W
The energy consumed was 122 J
The estimated remaining time is 3 hours, 32 minutes

Summary: 273.9 wakeups/second,  0.0 GPU ops/seconds, 0.0 VFS ops/sec and 11.8% CPU use

Power est.              Usage       Events/s    Category       Description
  6.63 W    100.0%                      Device         USB device: DELL DA300 (Bizlink)
  1.19 W      0.0%                      Device         Display backlight
  100 mW    100.0%                      Device         USB device: USB Optical Mouse
  100 mW    100.0%                      Device         USB device: Dell KB216 Wired Keyboard
  100 mW    100.0%                      Device         USB device: USB 10/100/1000 LAN (Realtek)
  254 uW     20.4 ms/s       0.8        Process        [PID 1835] /usr/bin/gnome-shell
    0 mW     28.9 ms/s      64.1        Process        [PID 1555] /usr/lib/xorg/Xorg vt2 -displayfd 3 -auth /run/user/5272/gdm/Xauthority -nolisten tcp -background none -noreset -kee
    0 mW     26.9 ms/s       4.4        Process        [PID 13647] firefox-nightly
    0 mW      4.7 ms/s      0.30        Process        [PID 19104] /usr/lib/firefox-nightly/firefox-bin -contentproc -childID 40 -isForBrowser -prefsLen 32894 -prefMapSize 243939 -js
    0 mW      4.4 ms/s       0.5        Process        [PID 22835] /usr/lib/thunderbird/thunderbird
    0 mW      3.2 ms/s      13.5        Process        [PID 23476] x2goclient
    0 mW      3.2 ms/s      0.20        Timer          hrtimer_wakeup
    0 mW      2.5 ms/s      0.25        Interrupt      [7] sched(softirq)
    0 mW      2.5 ms/s       0.8        Process        [PID 2629] /usr/libexec/gnome-terminal-server
    0 mW      2.2 ms/s      0.10        Process        [PID 14008] /usr/lib/firefox-nightly/firefox-bin -contentproc -childID 10 -isForBrowser -prefsLen 32843 -prefMapSize 243939 -js
    0 mW      2.0 ms/s      88.1        Timer          tick_sched_timer
    0 mW      1.9 ms/s       9.4        Process        [PID 15807] x2goclient
    0 mW      1.7 ms/s      30.6        Interrupt      [0] HI_SOFTIRQ
    0 mW      1.1 ms/s       8.5        Process        [PID 14042] /usr/lib/firefox-nightly/firefox-bin -contentproc -childID 10 -isForBrowser -prefsLen 32843 -prefMapSize 243939 -js
    0 mW      0.8 ms/s      0.00        Interrupt      [140] xhci_hcd
    0 mW      0.7 ms/s      0.25        Process        [PID 718] /usr/sbin/NetworkManager --no-daemon
    0 mW      0.7 ms/s       0.5        Process        [PID 13992] /usr/lib/firefox-nightly/firefox-bin -contentproc -childID 8 -isForBrowser -prefsLen 32843 -prefMapSize 243939 -jsI
    0 mW    634.4 us/s      0.00        Interrupt      [1] timer(softirq)
    0 mW    598.9 us/s      0.00        Timer          fq_flush_timeout
    0 mW    583.4 us/s      0.00        Process        [PID 13786] /usr/lib/firefox-nightly/firefox-bin -contentproc -childID 2 -isForBrowser -prefsLen 37383 -prefMapSize 243939 -jsI
    0 mW    572.4 us/s       0.7        kWork          kcryptd_crypt
    0 mW    559.4 us/s      0.00        Process        [PID 1506] /usr/bin/dbus-daemon --session --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only
    0 mW    487.4 us/s       0.3        Process        [PID 15821] powertop
    0 mW    462.3 us/s      0.00        Process        [PID 13655] firefox-nightly
    0 mW    411.4 us/s       0.6        Process        [PID 1008] /usr/libexec/upowerd
    0 mW    406.1 us/s      0.00        Timer          delayed_work_timer_fn
    0 mW    263.8 us/s      0.05        Process        [PID 407] /lib/systemd/systemd-journald
    0 mW    236.1 us/s      0.00        Process        [PID 2032] /usr/libexec/gsd-housekeeping
    0 mW    229.7 us/s      0.15        Interrupt      [9] RCU(softirq)
    0 mW    225.3 us/s      0.30        kWork          wb_workfn
    0 mW    224.0 us/s      0.25        Interrupt      [3] net_rx(softirq)
    0 mW    204.8 us/s       1.4        Process        [PID 19117] /usr/lib/firefox-nightly/firefox-bin -contentproc -childID 40 -isForBrowser -prefsLen 32894 -prefMapSize 243939 -js
    0 mW    194.3 us/s      0.20        Process        [PID 23493] /usr/bin/nxproxy -S nx/nx,options=/home/pmenzel/.x2go/S-pmenzel-50-1698304965_stDXFCE_dp24/options:50
    0 mW    191.6 us/s       0.5        Interrupt      [9] acpi
    0 mW    169.9 us/s       7.3        Process        [PID 16] [rcu_preempt]
    0 mW    166.5 us/s       2.3        Interrupt      [6] tasklet(softirq)
    0 mW    156.1 us/s      0.00        Process        [PID 18510] [kworker/2:0]
    0 mW    141.3 us/s      11.4        kWork          psi_avgs_work
    0 mW    129.8 us/s      0.00        Timer          process_timeout

Is that a Linux kernel or PowerTOP issue?

$ upower -i /org/freedesktop/UPower/devices/battery_BAT0
  native-path:          BAT0
  vendor:               SMP
  model:                DELL TP1GT61
  serial:               3808
  power supply:         yes
  updated:              Mo 13 Nov 2023 08:54:42 CET (23 seconds ago)
  has history:          yes
  has statistics:       yes
  battery
    present:             yes
    rechargeable:        yes
    state:               discharging
    warning-level:       none
    energy:              21,0976 Wh
    energy-empty:        0 Wh
    energy-full:         27,474 Wh
    energy-full-design:  59,9944 Wh
    energy-rate:         5,6696 W
    voltage:             7,847 V
    charge-cycles:       N/A
    time to empty:       3,7 hours
    percentage:          76%
    capacity:            45,7943%
    technology:          lithium-polymer
    icon-name:          'battery-full-symbolic'
  History (charge):
    1699862082	76,000	discharging
  History (rate):
    1699862082	5,670	discharging
    1699862052	7,083	discharging
    1699862022	11,894	discharging
    1699861992	5,578	discharging