Re: [Qemu-discuss] Why arm and aarch64 -M virt boards don't have graphics support?

[Peter Maydell]

On 23 May 2018 at 20:28, Ciro Santilli <address@hidden> wrote:
> On Mon, May 21, 2018 at 9:32 AM, Peter Maydell <address@hidden> wrote:
>> On 21 May 2018 at 00:26, Ciro Santilli <address@hidden> wrote:
>>> Do you know which options I might need to add to my  QEMU -M virt
>>> command to make it open a graphic window (and hopefully show the
>>> CONFIG_LOGO penguin)?
>>>
>>> For example on QEMU v2.12.0, the following boots fine but does not
>>> open an SDL graphical window like an analogous x86 command would:
>>>
>>> qemu-system-aarch64 \
>>> -serial mon:stdio \
>>> -M virt \
>>> -append 'root=/dev/vda console=ttyAMA0' \
>>> -cpu cortex-a57 \
>>> -kernel Image \
>>> -drive file='rootfs.ext2.qcow2,if=virtio,format=qcow2' \
>>
>> I'm guessing this command line is truncated. In general assuming
>
> Hmm, I have just double checked, and that was my full exact command,
> there was no -nographic option.

I assumed it was truncated because it has the trailing line-continuation
'\' character. Anyway...

> Then I noticed that it behaves differently between my Ubuntu 18.04 vs
> Ubuntu 16.04 machines: on 18.04, the SDL window does not open for
> aarch64, only for x86.

NB that x86 by default includes a VGA card, which is probably where
the difference is coming from there.

> Then, if I connect with -vnc :0 instead, I observe on both Ubuntus:
>
> * aarch64
> ** with -serial mon:stdio: GUI has only parallel, ctrl + alt + n does
> not switch to any other, monitor and serial on host terminal
> ** without -serial mon:stdio: GUI has 3 windows: serial, parallel and
> monitor, but no framebuffer
> * x86_64
> ** with -serial mon:stdio: GUI has two windows, framebuffer and
> parallel, serial and monitor on host terminal
> ** without -serial mon:stdio: GUI has 4 views: framebuffer, serial,
> parallel and monitor
>
> Could this be because the kernel is not configured properly, so QEMU
> does not open the framebuffer all?

I'm not sure what the behaviour of VNC and SDL is in the case
where there's no graphics device -- I really only ever use GTK.
This all sounds vaguely plausibly right, though: if something
(ie monitor or whatever) wants a graphical view it can get it.
If you add a graphic device to the VM (eg virtio-gpu) then it
ought to also have a graphical view.

thanks
-- PMM