Dear Linux folks,
On the Intel Kaby Lake laptop Dell XPS 13 9360 with Debian sid/unstable
and *powertop* 2.15-3, connecting a USB-C adapter like Dell DA300 or LMP
USB-C mini Dock (P/N 15954) [1] and connecting only an Ethernet cable
(module r8152 is used), the adapter gets very hot, and according to
PowerTOP it uses over 5 Watts – almost more as the laptop idling.
$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 0cf3:e300 Qualcomm Atheros Communications
QCA61x4 Bluetooth 4.0
Bus 001 Device 003: ID 04f3:2234 Elan Microelectronics Corp.
Touchscreen
Bus 001 Device 004: ID 0c45:670c Microdia Integrated Webcam HD
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 002: ID 2109:2820 VIA Labs, Inc. VL820 Hub
Bus 003 Device 003: ID 06c4:c412 Bizlink International Corp. DELL DA300
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 004 Device 002: ID 2109:0820 VIA Labs, Inc. VL820 Hub
Bus 004 Device 003: ID 0bda:8153 Realtek Semiconductor Corp.
RTL8153 Gigabit Ethernet Adapter
With `LANG= sudo powertop --auto-tune` it stays high.
PowerTOP:
```
The battery reports a discharge rate of 6.01 W
The energy consumed was 146 J
The estimated remaining time is 3 hours, 51 minutes
Summary: 384.6 wakeups/second, 0.0 GPU ops/seconds, 0.0 VFS ops/sec and
8.5% CPU use
Power est. Usage Events/s Category Description
5.94 W 0.0% Device Display backlight
5.23 W 100.0% Device USB device: USB
Optical Mouse (Logitech)
4.62 W 66.1% Device USB device: USB
10/100/1000 LAN (Realtek)
205 mW 100.0% Device USB device:
Fujitsu Keyboard (Fujitsu)
14.1 mW 13.5 ms/s 0.9 kWork intel_atomic_commit_work
```
At another time:
```
The battery reports a discharge rate of 10.5 W
The energy consumed was 235 J
The estimated remaining time is 2 hours, 20 minutes
Summary: 395.8 wakeups/second, 0.0 GPU ops/seconds, 0.0 VFS ops/sec and
23.8% CPU use
Power est. Usage Events/s Category Description
7.13 W 100.0% Device USB device: USB
10/100/1000 LAN (Realtek)
3.92 W 15.8% Device Display backlight
320 mW 0.0 us/s 0.00 Process [PID 1349]
/usr/bin/pipewire
63.6 mW 65.4 ms/s 0.5 Process [PID 4982]
/usr/lib/thunderbird/thunderbird
24.9 mW 25.6 ms/s 6.7 Process [PID 37753]
/usr/lib/firefox-nightly/firefox-bin -contentproc -isForBrowser
-prefsLen 36793 -prefMapSize 265654 -jsInitLe
14.7 mW 15.1 ms/s 0.5 kWork
intel_atomic_commit_work
```
The heat of the USB-C adapter might suggest, that it draws that much
power. What is your experience? Can you suggest something?
Kind regards,
Paul
[1]:
https://lmp-adapter.com/product/lmp-usb-c-mini-dock/?attribute_pa_color=silver
"LMP USB-C mini Dock (P/N 15954)"
