title: Android emulator failed to start after a successful aosp build
body: <p>Follow the official <a href="https://source.android.com/setup/build/building" rel="nofollow noreferrer">build guide</a>.
  I downloaded the master branch and built the aosp_arm-eng target. The build process was fine, but when I tried to start the emulator, it failed with the following logs:</p>
  <pre><code>.......
  emulator: GPU emulation enabled using 'host' mode
  emulator: Initializing hardware OpenGLES emulation support
  emulator: VERBOSE: MultiDisplay.cpp:312: create display 0
  emulator: VERBOSE: MultiDisplay.cpp:401: setDisplayPose 0 x 0 y 0 w 480 h 800 dpi 0
  cannot add library /media/kevin/Data/aosp/prebuilts/android-emulator/linux-x86_64/qemu/linux-x86_64/lib64/vulkan/libvulkan.so: failed
  added library /media/kevin/Data/aosp/prebuilts/android-emulator/linux-x86_64/lib64/vulkan/libvulkan.so
  cannot add library /media/kevin/Data/aosp/prebuilts/android-emulator/linux-x86_64/lib64/vulkan/libvulkan.so.1: full
  emulator: VERBOSE: load_config.cpp:242: Verified boot params were not found.
  .......
  emulator: Starting QEMU main loop
  emulator: Adding boot property: 'ro.opengles.version' = '196609'
  emulator: Adding boot property: 'qemu.sf.fake_camera' = 'both'
  emulator: Adding boot property: 'dalvik.vm.heapsize' = '512m'
  emulator: Adding boot property: 'qemu.hw.mainkeys' = '0'
  emulator: Adding boot property: 'qemu.sf.lcd_density' = '240'
  qemu-system-aarch64: -chardev socket,port=46269,host=localhost,nowait,nodelay,ipv6,id=modem: Failed to connect socket: Connection refused
  emulator: Done with QEMU main loop
  </code></pre>
  <p>I had searched around, and tried install some <a href="https://linuxconfig.org/install-and-test-vulkan-on-linux" rel="nofollow noreferrer">vulkan related packages</a>.</p>
  <p>I'd also tried to <a href="https://developer.android.com/studio/run/managing-avds" rel="nofollow noreferrer">create an Android Virtual Device</a> by using the built files,the avd just showed an empty black screen. But the AVDs created from the offical images works well on my computer.</p>
  <p>System Info:</p>
  <p>Ubunutu 20.04</p>
  <p>CPU: 14-Core Intel Xeon E5-2680 v4 (-MT MCP-) speed/min/max: 1199/1200/3300 MHz Kernel: 5.4.0-58-generic x86_64 Up: 1d 23h 10m</p>
  <p>Graphics:  Device-1: Advanced Micro Devices [AMD/ATI] Baffin [Radeon RX 550 640SP / RX 560/560X] driver: amdgpu v: kernel
  Display: x11 server: X.Org 1.20.8 driver: amdgpu resolution: 3840x2160~60Hz
  OpenGL: renderer: Radeon RX 560 Series (POLARIS11 DRM 3.35.0 5.4.0-58-generic LLVM 10.0.0) v: 4.6 Mesa 20.0.8</p>