I noticed twice the behaviour which I desribed in message #10 in Debian 10.3
("Buster", the currently stable Debian release) on the same hardware (Acer
Aspire E1-530 laptop), too.
I then applied the same steps as mentioned in message #10 .
This is the first time I rebooted my machine having applied these steps, and so
far the screen's brightness is at 100%.
This is information about Graphics info (card(s), driver, display protocol (if
available), display server, resolution:
xxx@punk:~$ inxi -G
Graphics: Device-1: Intel 3rd Gen Core processor Graphics driver: i915 v:
kernel.
Display: x11 server: X.Org 1.20.4 driver: intel resolution: 1366x768~60Hz.
OpenGL: renderer: Mesa DRI Intel Ivybridge Mobile v: 4.2 Mesa 18.3.6
xxx@punk:~
