Ubuntu 15.04 第二台显示器空白且 LED 闪烁

Question

我有一张带有 3 个 DVI 输出的 VisionTek Radeon 卡。我使用适配器将其中一个连接到 DVI 显示器，将另一个连接到 VGA 显示器。两个显示器均显示在设置|显示和 Catalyst 中，但 VGA 显示器始终空白且 LED 闪烁。

Screen 0: minimum 320 x 200, current 3200 x 1080, maximum 8192 x 8192
      DFP1 connected 1280x768+1920+0 (normal left inverted right x axis y axis) 477mm x 268mm
         1280x768      59.81*+
         1920x1080     60.00 +
         1680x1050     60.00  
         1400x1050     60.00  
         1600x900      60.00  
         1360x1024     60.00  
         1280x1024     60.02  
         1440x900      59.89  
         1280x960      60.02  
         1280x800      59.81  
         1152x864      60.00    75.00  
         1280x720      59.81  
         1024x768      70.07    60.00  
         800x600       60.32    56.25  
         640x480       67.00    59.94  
      DFP2 disconnected (normal left inverted right x axis y axis)
      DFP3 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 509mm x 286mm
         1920x1080     60.00*+
         1680x1050     59.95  
         1400x1050     59.95  
         1600x900      59.95  
         1360x1024     59.95  
         1280x1024     60.02  
         1440x900      59.89  
         1280x960      60.02  
         1280x800      59.81  
         1152x864      60.00    75.00  
         1280x768      59.81  
         1280x720      59.86  
         1024x768      70.07    60.00  
         800x600       60.32    56.25  
         640x480       66.61    59.94  

关于我配置错误的任何想法吗？