Comment 1 for bug 1530695

Same issue with my laptop. After fresh 16.04 install laptop's display active but blank.

# lshw -c video
  *-display
       description: VGA compatible controller
       product: Trinity [Radeon HD 7640G]
       vendor: Advanced Micro Devices, Inc. [AMD/ATI]
       physical id: 1
       bus info: pci@0000:00:01.0
       version: 00
       width: 32 bits
       clock: 33MHz
       capabilities: pm pciexpress msi vga_controller bus_master cap_list rom
       configuration: driver=radeon latency=0
       resources: irq:39 memory:c0000000-cfffffff ioport:5000(size=256) memory:d6000000-d603ffff

# xrandr
Screen 0: minimum 320 x 200, current 1440 x 900, maximum 16384 x 16384
LVDS connected (normal left inverted right x axis y axis)
   1366x768 59.99 + 40.00
   1280x720 59.86
   1152x768 59.78
   1024x768 59.92
   800x600 59.86
   848x480 59.66
   720x480 59.71
   640x480 59.38
VGA-0 connected primary 1440x900+0+0 (normal left inverted right x axis y axis) 408mm x 255mm
   1440x900 59.89*+ 74.98
   1280x1024 75.02 60.02
   1024x768 75.08 70.07 60.00
   832x624 74.55
   800x600 72.19 75.00 60.32 56.25
   640x480 75.00 72.81 66.67 60.00
   720x400 70.08
HDMI-0 disconnected (normal left inverted right x axis y axis)

I suppose this issue related to radeon driver, because on my previous installation(Ubuntu 14.04, fglrx driver) all worked fine.