$ xfce4-power-manager --debug
TRACE[xfpm-main.c:200] xfpm_start(): Starting the power manager
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for general-notification
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for lock-screen-suspend-hibernate
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for power-save-on-battery
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for enable-cpu-freq-control
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for critical-power-level
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for show-brightness-popup
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for change-brightness-on-key-events
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for show-tray-icon
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for hibernate-button-action
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for sleep-button-action
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for brightness-level-on-ac
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for brightness-level-on-battery
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for dpms-enabled
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for dpms-on-ac-off
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for dpms-on-battery-off
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for inactivity-on-ac
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for inactivity-on-battery
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for brightness-on-ac
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for brightness-on-battery
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for spin-down-on-ac-timeout
TRACE[xfpm-xfconf.c:156] xfpm_xfconf_load(): Using default configuration for spin-down-on-battery-timeout
TRACE[xfpm-power.c:1053] xfpm_power_get_power_devices(): Power device detected at : /org/freedesktop/UPower/devices/line_power_C172
TRACE[xfpm-power.c:1053] xfpm_power_get_power_devices(): Power device detected at : /org/freedesktop/UPower/devices/battery_C174
TRACE[xfpm-power.c:1011] xfpm_power_add_device(): Battery device detected at : /org/freedesktop/UPower/devices/battery_C174: ((XfpmDeviceType) XFPM_DEVICE_TYPE_BATTERY)
TRACE[xfpm-button.c:179] xfpm_button_xevent_key(): Grabbed key 124 : ((XfpmButtonKey) BUTTON_POWER_OFF)

(xfce4-power-manager:2453): xfce4-power-manager-WARNING **: could not map keysym 1008ffa8 to keycode

TRACE[xfpm-button.c:179] xfpm_button_xevent_key(): Grabbed key 213 : ((XfpmButtonKey) BUTTON_HIBERNATE)
TRACE[xfpm-button.c:179] xfpm_button_xevent_key(): Grabbed key 150 : ((XfpmButtonKey) BUTTON_SLEEP)
TRACE[xfpm-button.c:179] xfpm_button_xevent_key(): Grabbed key 233 : ((XfpmButtonKey) BUTTON_MON_BRIGHTNESS_UP)
TRACE[xfpm-button.c:179] xfpm_button_xevent_key(): Grabbed key 232 : ((XfpmButtonKey) BUTTON_MON_BRIGHTNESS_DOWN)
TRACE[xfpm-button.c:179] xfpm_button_xevent_key(): Grabbed key 244 : ((XfpmButtonKey) BUTTON_BATTERY)
TRACE[xfpm-battery.c:148] xfpm_battery_refresh_visible(): visible=TRUE: ((XfpmShowIcon) SHOW_ICON_WHEN_BATTERY_PRESENT)
TRACE[xfpm-battery.c:284] xfpm_battery_refresh_icon(): Battery state 4
TRACE[xfpm-power.c:1152] xfpm_power_refresh_adaptor_visible(): Tray icon configuration: : ((XfpmShowIcon) SHOW_ICON_WHEN_BATTERY_PRESENT)
TRACE[xfpm-power.c:1117] xfpm_power_hide_adapter_icon(): Hide adaptor icon
TRACE[xfpm-polkit.c:339] xfpm_polkit_init_data(): Using unix session polkit subject
TRACE[xfpm-polkit.c:426] xfpm_polkit_check_auth_intern(): Action=org.freedesktop.upower.suspend is authorized=TRUE
TRACE[xfpm-polkit.c:426] xfpm_polkit_check_auth_intern(): Action=org.freedesktop.upower.hibernate is authorized=TRUE
TRACE[xfpm-power.c:1152] xfpm_power_refresh_adaptor_visible(): Tray icon configuration: : ((XfpmShowIcon) SHOW_ICON_WHEN_BATTERY_PRESENT)
TRACE[xfpm-power.c:1117] xfpm_power_hide_adapter_icon(): Hide adaptor icon
TRACE[xfpm-polkit.c:426] xfpm_polkit_check_auth_intern(): Action=org.freedesktop.udisks.drive-set-spindown is authorized=TRUE
TRACE[xfpm-disks.c:170] xfpm_disks_get_is_auth_to_spin(): Is auth to spin down disks : 1
TRACE[xfpm-disks.c:147] xfpm_disks_set_spin_timeouts(): On Battery=0 spin_down_enabled=1 timeout=800

TRACE[xfpm-disks.c:101] xfpm_disks_enable_spin_down_timeouts(): Setting spin down timeout 800

** (xfce4-power-manager:2453): WARNING **: No outputs have backlight property
** (xfce4-power-manager:2453): DEBUG: executed /usr/sbin/xfpm-power-backlight-helper --get-max-brightness; retval: 1024
** (xfce4-power-manager:2453): DEBUG: xfpm_brightness_setup_helper: get-max-brightness returned -1
** (xfce4-power-manager:2453): DEBUG: no brightness controls available
TRACE[xfpm-polkit.c:209] xfpm_polkit_free_data(): Destroying Polkit data