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

[Ciro Santilli]

On Thu, May 24, 2018 at 10:08 AM, Peter Maydell
<address@hidden> wrote:
> 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

Ah, OK, if I pass -device virtio-gpu or any other display device from
under -device ?, then the framebuffer window does show up on 16.04.

Then I had to configure the Linux kernel with:

CONFIG_DRM=y
CONFIG_DRM_VIRTIO_GPU=y

and I get a penguin!!

Can you give me a wiki account with username cirosantilli so I can
update the info there?

> ought to also have a graphical view.
>
> thanks
> -- PMM