vfio: add vgpu edid support?

[Gerd Hoffmann]

  Hi,

> So, do you plan to use VFIO_DEVICE_GFX_EDID_SET dynamically? To change
> the display resolution during guest running?

Yes.

> Could you elaborate more on what the use case would be?

When the gtk or sdl window is resized by the user qemu will notify the
guest about the new window size.

GraphicHwOps->ui_info is the notification callback.

https://git.kraxel.org/cgit/qemu/commit/?h=sirius/edid&id=8334ef0362e80a9994d4c35d12c0e929568daeff

> Besides, I think the proposed "VFIO_DEVICE_GFX_EDID_SET" can also provide
> host a capability to trigger display monitor hot-plug event to guest, when host
> wants to temporarily turn off vfio/display.

That makes sense indeed.

> Qemu can pass a special edid to vendor driver to tell vendor driver to
> plug the guest display monitor out.

I'd add a field to vfio_device_gfx_edid_set instead, or use a flags bit.

cheers,
  Gerd