Black screen in QEmu for ARM-Ubuntu (how to get a graphical interface?)

Question

I host Ubuntu 16.04 on a virtual box from Windows 10. Inside Ubuntu 16.04 there is QEmu emulating an ARM processor running under Ubuntu Trusty (14.04).

When I start QEmu as follows, it shows a window titled QEMU , but a completely black client area:

 qemu-system-arm -smp 2 --drive format=raw,if=sd,file=vexpress-8G.img -kernel vmlinuz-3.13.0-24-generic-lpae -initrd initrd.img-3.13.0-24-generic-lpae -M vexpress-a15 -serial stdio -m 2048 -append 'root=/dev/mmcblk0 rw mem=2048M raid=noautodetect rootwait console=ttyAMA0,38400n8 devtmpfs.mount=0' -dtb ./vexpress-v2p-ca15-tc1.dtb 

The guest OS console (ARM-Ubuntu) works, boot messages are displayed in the same terminal where the qemu-system-arm command was executed. But when I type the startx command, it shows errors:

 Loading extension GLX (EE) Fatal server error: (EE) no screens found(EE) (EE) Please consult the The X.Org Foundation support at http://wiki.x.org for help. (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information. (EE) (EE) Server terminated with error (1). Closing log file. xinit: giving up xinit: unable to connect to X server: Connection refused xinit: server error 

/var/log/Xorg.0.log contains the following:

 [ 214.406] X.Org X Server 1.15.1 Release Date: 2014-04-13 [ 214.411] X Protocol Version 11, Revision 0 [ 214.411] Build Operating System: Linux 3.2.0-58-highbank armv7l Ubuntu [ 214.412] Current Operating System: Linux VM-Ubuntu1 3.13.0-24-generic-lpae #46-Ubuntu SMP Thu Apr 10 21:01:14 UTC 2014 armv7l [ 214.413] Kernel command line: root=/dev/mmcblk0 rw mem=2048M raid=noautodetect rootwait console=ttyAMA0,38400n8 devtmpfs.mount=0 [ 214.416] Build Date: 16 April 2014 01:41:53PM [ 214.417] xorg-server 2:1.15.1-0ubuntu2 (For technical support please see http://www.ubuntu.com/support) [ 214.418] Current version of pixman: 0.30.2 [ 214.418] Before reporting problems, check http://wiki.x.org to make sure that you have the latest version. [ 214.419] Markers: (--) probed, (**) from config file, (==) default setting, (++) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown. [ 214.431] (==) Log file: "/var/log/Xorg.0.log", Time: Fri Aug 19 16:21:42 2016 [ 214.446] (==) Using system config directory "/usr/share/X11/xorg.conf.d" [ 214.461] (==) No Layout section. Using the first Screen section. [ 214.462] (==) No screen section available. Using defaults. [ 214.463] (**) |-->Screen "Default Screen Section" (0) [ 214.463] (**) | |-->Monitor "<default monitor>" [ 214.468] (==) No monitor specified for screen "Default Screen Section". Using a default monitor configuration. [ 214.470] (==) Automatically adding devices [ 214.471] (==) Automatically enabling devices [ 214.471] (==) Automatically adding GPU devices [ 214.475] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist. [ 214.476] Entry deleted from font path. [ 214.476] (WW) The directory "/usr/share/fonts/X11/100dpi/" does not exist. [ 214.477] Entry deleted from font path. [ 214.478] (WW) The directory "/usr/share/fonts/X11/75dpi/" does not exist. [ 214.478] Entry deleted from font path. [ 214.479] (WW) The directory "/usr/share/fonts/X11/100dpi" does not exist. [ 214.479] Entry deleted from font path. [ 214.480] (WW) The directory "/usr/share/fonts/X11/75dpi" does not exist. [ 214.480] Entry deleted from font path. [ 214.481] (==) FontPath set to: /usr/share/fonts/X11/misc, /usr/share/fonts/X11/Type1, built-ins [ 214.482] (==) ModulePath set to "/usr/lib/arm-linux-gnueabihf/xorg/extra-modules,/usr/lib/xorg/extra-modules,/usr/lib/xorg/modules" [ 214.484] (II) The server relies on udev to provide the list of input devices. If no devices become available, reconfigure udev or disable AutoAddDevices. [ 214.485] (II) Loader magic: 0xb7008f18 [ 214.486] (II) Module ABI versions: [ 214.486] X.Org ANSI C Emulation: 0.4 [ 214.487] X.Org Video Driver: 15.0 [ 214.487] X.Org XInput driver : 20.0 [ 214.489] X.Org Server Extension : 8.0 [ 214.495] Initializing built-in extension Generic Event Extension [ 214.496] Initializing built-in extension SHAPE [ 214.497] Initializing built-in extension MIT-SHM [ 214.497] Initializing built-in extension XInputExtension [ 214.498] Initializing built-in extension XTEST [ 214.498] Initializing built-in extension BIG-REQUESTS [ 214.499] Initializing built-in extension SYNC [ 214.500] Initializing built-in extension XKEYBOARD [ 214.500] Initializing built-in extension XC-MISC [ 214.501] Initializing built-in extension SECURITY [ 214.501] Initializing built-in extension XINERAMA [ 214.503] Initializing built-in extension XFIXES [ 214.503] Initializing built-in extension RENDER [ 214.504] Initializing built-in extension RANDR [ 214.505] Initializing built-in extension COMPOSITE [ 214.505] Initializing built-in extension DAMAGE [ 214.506] Initializing built-in extension MIT-SCREEN-SAVER [ 214.506] Initializing built-in extension DOUBLE-BUFFER [ 214.507] Initializing built-in extension RECORD [ 214.507] Initializing built-in extension DPMS [ 214.508] Initializing built-in extension Present [ 214.508] Initializing built-in extension DRI3 [ 214.509] Initializing built-in extension X-Resource [ 214.509] Initializing built-in extension XVideo [ 214.510] Initializing built-in extension XVideo-MotionCompensation [ 214.512] Initializing built-in extension SELinux [ 214.513] Initializing built-in extension XFree86-VidModeExtension [ 214.514] Initializing built-in extension XFree86-DGA [ 214.514] Initializing built-in extension XFree86-DRI [ 214.515] Initializing built-in extension DRI2 [ 214.516] (II) LoadModule: "glx" [ 214.537] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so [ 214.612] (II) Module glx: vendor="X.Org Foundation" [ 214.613] compiled for 1.15.1, module version = 1.0.0 [ 214.614] ABI class: X.Org Server Extension, version 8.0 [ 214.615] (==) AIGLX enabled [ 214.616] Loading extension GLX [ 214.619] (==) Matched modesetting as autoconfigured driver 0 [ 214.619] (==) Matched fbdev as autoconfigured driver 1 [ 214.620] (==) Assigned the driver to the xf86ConfigLayout [ 214.621] (II) LoadModule: "modesetting" [ 214.625] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so [ 214.628] (II) Module modesetting: vendor="X.Org Foundation" [ 214.629] compiled for 1.15.0, module version = 0.8.1 [ 214.630] Module class: X.Org Video Driver [ 214.630] ABI class: X.Org Video Driver, version 15.0 [ 214.631] (II) LoadModule: "fbdev" [ 214.635] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so [ 214.638] (II) Module fbdev: vendor="X.Org Foundation" [ 214.639] compiled for 1.15.0, module version = 0.4.4 [ 214.639] Module class: X.Org Video Driver [ 214.640] ABI class: X.Org Video Driver, version 15.0 [ 214.642] (II) modesetting: Driver for Modesetting Kernel Drivers: kms [ 214.644] (II) FBDEV: driver for framebuffer: fbdev [ 214.647] (--) using VT number 7 [ 214.652] (WW) Falling back to old probe method for modesetting [ 214.656] (EE) open /dev/dri/card0: No such file or directory [ 214.657] (WW) Falling back to old probe method for fbdev [ 214.658] (II) Loading sub module "fbdevhw" [ 214.658] (II) LoadModule: "fbdevhw" [ 214.663] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so [ 214.666] (II) Module fbdevhw: vendor="X.Org Foundation" [ 214.669] compiled for 1.15.1, module version = 0.0.2 [ 214.669] ABI class: X.Org Video Driver, version 15.0 [ 214.671] (EE) open /dev/fb0: No such file or directory [ 214.672] (EE) No devices detected. [ 214.674] (==) Matched modesetting as autoconfigured driver 0 [ 214.674] (==) Matched fbdev as autoconfigured driver 1 [ 214.675] (==) Assigned the driver to the xf86ConfigLayout [ 214.675] (II) LoadModule: "modesetting" [ 214.679] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so [ 214.680] (II) Module modesetting: vendor="X.Org Foundation" [ 214.681] compiled for 1.15.0, module version = 0.8.1 [ 214.681] Module class: X.Org Video Driver [ 214.682] ABI class: X.Org Video Driver, version 15.0 [ 214.682] (II) UnloadModule: "modesetting" [ 214.683] (II) Unloading modesetting [ 214.685] (II) Failed to load module "modesetting" (already loaded, -1205831248) [ 214.686] (II) LoadModule: "fbdev" [ 214.689] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so [ 214.690] (II) Module fbdev: vendor="X.Org Foundation" [ 214.691] compiled for 1.15.0, module version = 0.4.4 [ 214.691] Module class: X.Org Video Driver [ 214.692] ABI class: X.Org Video Driver, version 15.0 [ 214.692] (II) UnloadModule: "fbdev" [ 214.694] (II) Unloading fbdev [ 214.695] (II) Failed to load module "fbdev" (already loaded, -1205831248) [ 214.695] (II) modesetting: Driver for Modesetting Kernel Drivers: kms [ 214.696] (II) FBDEV: driver for framebuffer: fbdev [ 214.699] (++) using VT number 7 [ 214.699] (WW) xf86OpenConsole: setpgid failed: Operation not permitted [ 214.700] (WW) xf86OpenConsole: setsid failed: Operation not permitted [ 214.701] (WW) Falling back to old probe method for modesetting [ 214.702] (EE) open /dev/dri/card0: No such file or directory [ 214.702] (WW) Falling back to old probe method for fbdev [ 214.703] (II) Loading sub module "fbdevhw" [ 214.703] (II) LoadModule: "fbdevhw" [ 214.708] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so [ 214.708] (II) Module fbdevhw: vendor="X.Org Foundation" [ 214.709] compiled for 1.15.1, module version = 0.0.2 [ 214.710] ABI class: X.Org Video Driver, version 15.0 [ 214.710] (EE) open /dev/fb0: No such file or directory [ 214.711] (EE) No devices detected. [ 214.711] (EE) Fatal server error: [ 214.714] (EE) no screens found(EE) [ 214.716] (EE) Please consult the The X.Org Foundation support at http://wiki.x.org for help. [ 214.717] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information. [ 214.718] (EE) [ 214.723] (EE) Server terminated with error (1). Closing log file. 

Below are all the steps for creating and loading an ARM-Ubuntu image (based on https://wiki.ubuntu.com/Kernel/Dev/QemuARMVexpress ):

 # 1) setup the rootfs sudo apt-get install qemu-user-static qemu-system-arm mkdir vexpress cd vexpress mkdir qemu-img # Create 8-GB image dd if=/dev/zero of=./vexpress-8G.img bs=8M count=1024 sudo losetup -f ./vexpress-8G.img sudo mkfs.ext4 /dev/loop0 sudo mount /dev/loop0 qemu-img # Bootstrap Ubuntu Trusty armhf rootfs in the qemu-img directory # For Ubuntu versions later than Trusty some commands fail # For Ubuntu versions before Saucy there is no port to ARM # Ubuntu Saucy is not supported anymore sudo qemu-debootstrap --arch=armhf trusty qemu-img sudo cp `which qemu-arm-static` qemu-img/usr/bin/ # setup serial console, apt repositories and network sudo chroot qemu-img sed 's/tty1/ttyAMA0/g' /etc/init/tty1.conf > /etc/init/ttyAMA0.conf echo "deb http://ports.ubuntu.com trusty main restricted multiverse universe" > /etc/apt/sources.list apt-get update echo -e "\nauto eth0\niface eth0 inet dhcp" >> /etc/network/interfaces # root password passwd # 2) pick and install a kernel # Fix locale problems http://askubuntu.com/questions/162391/how-do-i-fix-my-locale-issue locale sudo locale-gen "be_BY.UTF-8" sudo locale-gen "en_US" sudo locale-gen "en_US.UTF-8" sudo dpkg-reconfigure locales apt-get install wget ca-certificates wget https://launchpad.net/ubuntu/+archive/primary/+files/linux-image-3.13.0-24-generic-lpae_3.13.0-24.46_armhf.deb dpkg -i linux-image-3.13.0-24-generic-lpae_3.13.0-24.46_armhf.deb # So far I'm getting the following warnings: # Warning: cannot read table of mounted file systems: No such file or directory # warning: failed to read mtab # !!! press CTRL+D to exit the chroot ^D # 3) Boot it up # copy kernel, initrd and dtb files sudo cp qemu-img/boot/vmlinuz-3.13.0-24-generic-lpae . sudo cp qemu-img/boot/initrd.img-3.13.0-24-generic-lpae . sudo cp qemu-img/lib/firmware/3.13.0-24-generic-lpae/device-tree/vexpress-v2p-ca15-tc1.dtb . # umount the rootfs img sudo umount qemu-img sudo chmod 777 vmlinuz-3.13.0-24-generic-lpae sudo chmod 777 initrd.img-3.13.0-24-generic-lpae sudo chmod 777 vexpress-v2p-ca15-tc1.dtb sudo chmod 777 vexpress-8G.img # http://unix.stackexchange.com/questions/167165/how-to-pass-ctrl-c-in-qemu # Allow Ctrl+C and Ctrl+Z on guest, changing them on host to Ctrl+] and Ctrl+[ stty intr ^] stty susp ^j qemu-system-arm -smp 2 --drive format=raw,if=sd,file=vexpress-8G.img -kernel vmlinuz-3.13.0-24-generic-lpae -initrd initrd.img-3.13.0-24-generic-lpae -M vexpress-a15 -serial stdio -m 2048 -append 'root=/dev/mmcblk0 rw mem=2048M raid=noautodetect rootwait console=ttyAMA0,38400n8 devtmpfs.mount=0' -dtb ./vexpress-v2p-ca15-tc1.dtb 

I do not know if the problem was Ubuntu (software) or QEmu (hardware emulation).