nvidia.NVreg_EnableBacklightHandler=1
to grub fixes brighness hotkeys, they work fine now, and brightness change notifications appeared as well.
However some strange interaction between nvidia-setting app and xfce brightness control still happens: changing brightness on a color correction tab of nvidia-settings does not affect xfce panel power-manager plugin and vice verca. But maybe they just change different properties, i'm not sure here.
can't get this work, video card is nvidia with proprietary drivers installed.
Running xfce4-power-manager with --debug gives
TRACE[xfpm-button.c:118] xfpm_button_filter_x_events(): Key press: ((XfpmButtonKey) BUTTON_MON_BRIGHTNESS_UP)
TRACE[xfpm-manager.c:281] xfpm_manager_button_pressed_cb(): Received button press event: ((XfpmButtonKey) BUTTON_MON_BRIGHTNESS_UP)
but nothing happens.
Changing brightness via nvidia control panel works as well as decreasing brightness after inactivity period set in power manager options.
Regards,
Alexander