Ubuntu 18.04 Нет звука от HDMI

У меня Ubuntu 18.04 работает на Macbook 2008 года. Я не могу заставить звук HDMI работать. Я перепробовал все, включая переустановку nvidia, lightdm и обновление. :( Ничего не работает. Пожалуйста, помогите.

мой вывод из xrandr:

Screen 0: minimum 320 x 200, current 1280 x 800, maximum 8192 x 8192
LVDS-1 connected primary 1280x800+0+0 (normal left inverted right x axis y axis) 286mm x 179mm
   1280x800      60.22*+  59.99    59.97    59.81    59.91  
   1280x720      60.00    59.99    59.86    59.74  
   1024x768      60.04    60.00    59.95  
   960x720       60.00  
   928x696       60.05  
   896x672       60.01  
   1024x576      59.95    59.96    59.90    59.82  
   960x600       59.93    60.00  
   960x540       59.96    59.99    59.63    59.82  
   800x600       60.00    60.32    59.96    56.25  
   840x525       60.01    59.88  
   864x486       59.92    59.57  
   800x512       60.17  
   700x525       59.98  
   800x450       59.95    59.82  
   640x512       60.02  
   720x450       59.89  
   700x450       59.96    59.88  
   640x480       60.00    59.94    59.94  
   720x405       59.51    58.99  
   720x400       59.97  
   684x384       59.88    59.85  
   680x384       59.80    59.96  
   640x400       59.88    59.98    59.96  
   576x432       60.06  
   640x360       59.86    59.83    59.84    59.32  
   640x350       59.84  
   512x384       60.00  
   512x288       60.00    59.92  
   480x270       59.63    59.82  
   400x300       60.32    56.34  
   432x243       59.92    59.57  
   320x240       60.05  
   360x202       59.51    59.13  
   320x180       59.84    59.32  
DP-1 connected 1280x800+0+0 (normal left inverted right x axis y axis) 1366mm x 768mm
   1366x768      59.79 +
   1920x1080i    60.00    50.00    59.94  
   1920x1080     30.00    25.00    24.00    29.97    23.98  
   1360x768      59.80    59.96  
   1280x800      59.81    59.91* 
   1152x864      60.00    59.97  
   1280x768      59.87  
   1280x720      59.86    60.00    50.00    59.94    59.74  
   1024x768      70.07    60.00  
   1024x576      59.96    59.90    59.82  
   960x600       60.00  
   960x540       59.96    59.99    59.63    59.82  
   800x600       70.00    65.00    60.00    60.32    56.25  
   840x525       69.88    60.01    59.88  
   864x486       59.92    59.57  
   720x576       50.00  
   800x512       60.17  
   700x525       70.06    59.98  
   800x450       59.95    59.82  
   720x480       60.00    59.94  
   640x512       60.02  
   720x450       59.89  
   700x450       59.96    59.88  
   640x480       60.00    60.00    59.94  
   720x405       59.51    58.99  
   720x400       70.08  
   684x384       59.88    59.85  
   680x384       59.80    59.96  
   640x400       59.88    59.98  
   576x432       70.00    60.06  
   640x360       59.86    59.83    59.84    59.32  
   512x384       70.07    60.00  
   512x288       60.00    59.92  
   480x270       59.63    59.82  
   400x300       60.32    56.34  
   432x243       59.92    59.57  
   320x240       60.05  
   360x202       59.51    59.13  
   320x180       59.84    59.32