AMDGPU_DM_DEFAULT_MAX_BACKLIGHT
#define AMDGPU_DM_MIN_SPREAD ((AMDGPU_DM_DEFAULT_MAX_BACKLIGHT - AMDGPU_DM_DEFAULT_MIN_BACKLIGHT) / 2)
if (caps->max_input_signal > AMDGPU_DM_DEFAULT_MAX_BACKLIGHT ||
spread > AMDGPU_DM_DEFAULT_MAX_BACKLIGHT ||
caps->max_input_signal = AMDGPU_DM_DEFAULT_MAX_BACKLIGHT;
caps->max_input_signal = AMDGPU_DM_DEFAULT_MAX_BACKLIGHT;