Re: [PATCH 00/11] OvmfPkg, ArmVirtPkg: GOP driver for the VirtIo GPU (virtio-gpu-pci)

[Laszlo Ersek <lersek@redhat.com>]

On 08/19/16 14:49, Laszlo Ersek wrote:

> - Also tested loading and launching Linux from GRUB. Here the results
>   differ of course: x86_64 Fedora 24 drives virtio-gpu-pci with its
>   native driver without problems, whereas AARCH64 Fedora 23 doesn't even
>   look for virtio-gpu-pci, apparently.

Update:

Once booted from GRUB -- on top of OVMF / ArmVirtQemu respectively --,
both x86_64 and aarch64 Fedora *24* guests work well with
virtio-gpu-pci, as far as the character console (tty1, "virtiodrmfb") is
concerned.

However, for getting an X.org graphical environment (such as Xfce) to
work with virtio-gpu-pci, more gymnastics are needed in the guest, on
both guest arches.

This is because X.org considers "virtio-gpu-pci" a secondary graphics
card, and it won't use it even in a single-head setup *unless* the BusID
option is specified in the X.org config file, in the Device section.
Refer to <http://linux.die.net/man/5/xorg.conf>:

  BusID bus-id  [...] when using a secondary graphics card in a
                single-head configuration, this entry is mandatory

After I placed

  Section "Screen"
    Identifier "Default Screen"
    Device     "Default Device"
    Monitor    "Default Monitor"
  EndSection

  Section "Device"
    Identifier "Default Device"
    Driver     "modesetting"
    BusID      "PCI:0:1:0"
  EndSection

  Section "Monitor"
    Identifier "Default Monitor"
    Option     "PreferredMode"   "1024x768"
  EndSection

in

  /etc/X11/xorg.conf.d/01-resolution.conf

Xfce too is working fine for me. (Note that BusID must match the PCI
$BUS/$DEV/$FUN that QEMU assigns to virtio-gpu-pci, either
automatically, or in response to the user's "-device
virtio-gpu-pci,addr=$DEV" property.)

I guess if someone is into xserver development, this could be made a bit
more convenient, because for aarch64/KVM guests at least, virtio-gpu-pci
should be considered a primary (not secondary) graphics card.

Anyway, here's a screenshot:

http://people.redhat.com/lersek/virtio-gpu-pci-xorg-xfce.png

Thanks
Laszlo