Emerge.Config.Backlight (Emerge v0.5.1)

The panel backlight managed by a DRM output. Set this record as Emerge.Config.DRM.backlight; it does not apply to desktop windows.

%Emerge.Config{
  output: %Emerge.Config.DRM{
    backlight: %Emerge.Config.Backlight{
      device: "/sys/class/backlight/panel",
      brightness: 0.5
    }
  },
  renderer: %Emerge.Config.Renderer{api: :opengl}
}

Replace the example device path with your panel's actual backlight path.

Fields

device — :auto (default), an absolute sysfs backlight path, or nil to leave brightness unmanaged. Automatic selection requires a clear association with the chosen connector. No associated backlight is acceptable unless you request brightness; an ambiguous association is an error.
brightness — a number from 0 to 1, rounded to the device's supported levels. 0.5 requests half its numeric range, not a perceptual brightness curve. The default nil uses the original requested brightness. Returning to nil restores that original value, including after renderer recovery.

Brightness 0 is not display-off. Set DRM.display to :off to blank the display. A brightness change while off is used when the display turns on again. Requesting brightness with device: nil is invalid.

Changing settings

Brightness can change through config with explicit OpenGL, Vulkan or raster (CPU or GPU-upload presentation). Changing device requires a new viewport. Avoid writing the same backlight from another process while Emerge manages it. Stopping a managed display leaves its backlight dark.

Summary

Types

device()

Automatic association, no management, or an absolute sysfs backlight device path.

normalized_t()

Canonical form after nested keyword records have been expanded.

options()

Typed keyword shorthand accepted in this record's parent field.

t()