Re: [Qemu-devel] [RfC PATCH 0/3] sdl2: add opengl rendering support

[Gerd Hoffmann <kraxel@redhat.com>]

  Hi,

> Do you have a case in mind where the device emulation needs to know that?
> As opposed to "always need opengl" or "never needs opengl".

virtio-gpu has optional opengl support, and ideally the default behavior
is 'enable opengl support in case the UI supports it'.

> But you'd still need to know the UI in order to have a decent default.  For
> example should "-display vnc" should disable opengl by default (it's not
> in your list above)?  "-display egl" probably should enable it.

For SDL I'd like to have it initially disabled by default, then later
when it proved to be stable flip the default to enabled.

> Perhaps "-display" could be processed in two steps.

Hmm, that could work.  Have some ${ui}_early_init(), called when
parameters are parsed, to figure whenever opengl is available (and
possibly have different opengl-enable defaults per UI) but don't do full
initialization yet.

cheers,
  Gerd