How to switch the screen (EX including HDMI audio switching) in Linux?

For ATI graphics card

By default, the external display as long as a connection is successful, it will automatically pop-up display resolution configuration tool. However, if the tool did not Popup automatically, you need to find this tool in the following ways:

Please click on the icon on the lower left corner of the desktop:

Start → Favorities → System Settings → Display and Monitor

Also, can open the following ATI driver management tool:

Please click on the icon on the lower left corner of the desktop (the Start button) → applications → Settings → AMD Catalyst Control Center (Management)

1 VGA interface, you can press the FN and the F7 key to switch the display, there are three main state:

1. The first switch, external monitor only single-screen display. (External screen is the highest resolution)
   
2. After the second switch, if it is dual display. When the laptop screen and external display screen are lit, you check on the [unified output] (Unify outputs), and then click [Application] desktop position and the resolution of the two monitors can be unified. As follows:
   
   
   
   
3. The third switch for single-screen laptop.
   For HDMI interface, please press the FN and F7 key screen switching
   By default, the HDMI connected, will automatically jump to dual display. But generally cut the screen there are three cases:
   
   
   • The first switch, dual display:
     
     
     1. If the local display outside the range of the screen, an external display not stretch to full screen. You need to check the KDE settings the unified output (Unify outputs), click the Apply button. After click on the lower right (as shown below, to check on the top left of the Unity outputs
        
        
        
        
     2. Then, you click on the lower left corner of the icon on the desktop (ie Start button) → applications → Settings → AMD Catalyst Control Center (Management)
        
        The open ATI graphics driver management tool, you choose in the left column option Display Manager [Scalling Option] → DTV (2) option, then select the right-hand column of the adjustment [Adjustments] election tab. Drag the button, drag the zoom options in this tab to 0% (overscan [Overscan]) position. After confirmation, click Apply.
        
        
        
        
        
        
     3. Second switch for local single screen display.
        
     4. Third switch, a single-screen display for external monitor.
        This state external monitor can not display the normal resolution can do, such as the above (2) Switch operation.
        
        For VGA interface
        Specifically, you can press the FN and F7 key to switch between VGA interface display when switching three states:
        
        1. External single-screen display state. (External screen is the highest resolution)
        2. Dual display state. This time, when the laptop and external monitor simultaneously lit, you need to check [unified output】 → 【applications in], as shown below:
           
           
           
           
        3. Local single-screen display status.
        
        
        For HDMI interface, Press FN and F7 key while the screen switching
        Its setting is relatively simple, in particular also has three states:
        
        
        1. first press FN and F7 key to switch the screen for external single-screen display. (External screen maximum resolution.)
        2. A second press the the FN F7 key to switch the screen, dual display, you need to check [unified output] (Unify outputs) [Application]
           
           
           
           
           
           
        3. The third press FN and F7 key to switch the screen, the laptop local single-screen display, the external display does not show.