On PC file /sys/class/backlight/.../max_brightness can contain 0 when backlight control is not supported. Added check helps to avoid dividing by zero and printing NaN. --- src/devices/backlight.cpp | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/src/devices/backlight.cpp b/src/devices/backlight.cpp index b8c9147..82cb1e0 100644 --- a/src/devices/backlight.cpp +++ b/src/devices/backlight.cpp @@ -145,6 +145,9 @@ double backlight::utilization(void) { double p; + if (max_level == 0) + return 0.0; + p = 100.0 * (end_level + start_level) / 2 / max_level; return p; }