When I lock my screen using Ctrl+Alt+L, my screen goes blank. I am happy with this.
However, the back-light seems to turn off and on every around 5 seconds, even though the screen stays black. It's possible to see that the back-light turns off and on since the screen "blackness" changes.
I assume this behavior eats a lot of my battery when it shouldn't. How can I debug/fix it?
The laptop is a HP stream 14. Kernel version 4.15.0-58-generic, but I'm not using HWE. I didn't know about HWE, but as the model is now some years old I'm not sure it'd make a difference?
sudo lshw -C video:
*-display description: VGA compatible controller product: Atom/Celeron/Pentium Processor x5-E8000/J3xxx/N3xxx Integrated Graphics Controller vendor: Intel Corporation physical id: 2 bus info: pci@0000:00:02.0 version: 35 width: 64 bits clock: 33MHz capabilities: pm msi vga_controller bus_master cap_list rom configuration: driver=i915 latency=0 resources: irq:121 memory:90000000-90ffffff memory:80000000-8fffffff ioport:1000(size=64) memory:c0000-dffff