screen brightness control - macbook pro mid2009

Hi all, I can't adjust screen brightness on my macbook pro mid-2009 13-inch.

Thank you in advance for your support.

Here my system information (I hope this helps...):

System: Kernel: 6.8.0-45-generic arch: x86_64 bits: 64 compiler: gcc v: 13.2.0 clocksource: hpet Desktop: Xfce v: 4.18.1 tk: Gtk v: 3.24.41 wm: xfwm4 v: 4.18.0 with: xfce4-panel tools: light-locker vt: 7 dm: LightDM v: 1.30.0 Distro: Linux Mint 22 Wilma base: Ubuntu 24.04 noble Machine: Type: Laptop System: Apple product: MacBookPro5,5 v: 1.0 serial: Chassis: type: 10 v: Mac-F2268AC8 serial: Mobo: Apple model: Mac-F2268AC8 serial: uuid: UEFI: Apple v: MBP55.88Z.00AC.B03.0906151708 date: 06/15/09

Graphics: Device-1: NVIDIA C79 [GeForce 9400M] vendor: Apple driver: nouveau v: kernel arch: Tesla ports: active: LVDS-1 empty: none bus-ID: 02:00.0 chip-ID: 10de:0863 class-ID: 0300 temp: 65.0 C Device-2: Apple Built-in iSight driver: uvcvideo type: USB rev: 2.0 speed: 480 Mb/s lanes: 1 bus-ID: 1-4:3 chip-ID: 05ac:8507 class-ID: 0e02 serial: Display: x11 server: X.Org v: 21.1.11 with: Xwayland v: 23.2.6 compositor: xfwm4 v: 4.18.0 driver: X: loaded: modesetting unloaded: fbdev,vesa dri: nouveau gpu: nouveau display-ID: :0.0 screens: 1 Screen-1: 0 s-res: 1280x800 s-dpi: 96 s-size: 338x211mm (13.31x8.31") s-diag: 398mm (15.69") Monitor-1: LVDS-1 model: Apple 0x9cbd res: 1280x800 hz: 60 dpi: 114 size: 286x179mm (11.26x7.05") diag: 337mm (13.3") modes: max: 1280x800 min: 640x350 API: EGL v: 1.5 hw: drv: nvidia nouveau platforms: device: 0 egl: 1.4 drv: nouveau device: 1 drv: swrast gbm: egl: 1.4 drv: nouveau surfaceless: egl: 1.4 drv: nouveau x11: egl: 1.4 drv: nouveau inactive: wayland API: OpenGL v: 4.5 compat-v: 3.3 vendor: mesa v: 24.0.9-0ubuntu0.1 glx-v: 1.4 direct-render: yes renderer: NVAC device-ID: 10de:0863

org.xfce.powermanager 4.18.3