I'm running Manjaro on an old (2008?) 13" Macbook. It worked brilliantly for a few months, until recently the screen backlight has started switching off randomly, usually within a minute of booting. A temporary hack to is to set the backlight off and on again with xbacklight, however it then turns itself off again almost instantly. I wonder if two drivers are fighting for control?
Things I've tried:
- Adding the various acpi= options (none, native, vendor, video) in grub
- Toggling 'Handle display brightness keys' and 'Display power management' settings in XFCE power manager
- Upgrading kernel from 4.14 (was working fine previously) to 4.16
None of these have worked. When I used the acpi grub options there was still only intel_backlight listed under /sys/class/backlight/, although acpi appears to be installed and running. When the screen switches off, intel_backlight/brightness is equal to intel_brightness/max_brightness, and when I press the fn keys the brightness value in that file changes without any change to the actual backlight!
Any suggestions where else I could be looking? System details are below.
$ inxi -Fi System: Host: r2-d2 Kernel: 4.16.14-2-MANJARO x86_64 bits: 64 Desktop: N/A Distro: Manjaro Linux 17.1.10 Hakoila Machine: Type: Unknown System: Apple product: MacBook3,1 v: 1.0 serial: <root required> Mobo: Apple model: Mac-F22788C8 v: PVT serial: <root required> UEFI: Apple v: MB31.88Z.008E.B02.0803051832 date: 03/05/08 CPU: Topology: Dual Core model: Intel Core2 Duo T7500 bits: 64 type: MCP L2 cache: 4096 KiB Speed: 798 MHz min/max: 800/2200 MHz Core speeds (MHz): 1: 1110 2: 1128 Graphics: Card-1: Intel Mobile GM965/GL960 Integrated Graphics driver: i915 v: kernel Display: x11 server: N/A driver: intel unloaded: fbdev,modesetting,vesa resolution: <xdpyinfo missing> OpenGL: renderer: Mesa DRI Intel 965GM v: 2.1 Mesa 18.1.1