title: Linux Framebuffer modes
body: <p>I am currently working on embedded linux framebuffers. I know how to display the available resolutions of my system by typing:</p>
  
  <pre><code>cat /sys/class/graphics/fb0/modes
  </code></pre>
  
  <p>This gives me a list of resolutions, for instance:</p>
  
  <pre><code>U:720x576p-50
  D:1920x1080p-50
  D:1280x720p-50
  D:1920x1080i-60
  D:1920x1080i-50
  U:1440x900p-60
  S:1280x1024p-60
  V:1024x768p-60
  V:800x600p-60
  V:640x480p-60
  D:1280x720p-60
  D:1920x1080p-60
  </code></pre>
  
  <p>I would like to know what does the first character of each lines mean (S, U, V or D).
  Is there a standard/documentation listing all the possible characters?</p>