Re: [PATCH] Add virtio gpu driver.

[Dave Airlie <airlied@gmail.com>]

On 25 March 2015 at 08:50, Daniel Stone <daniel@fooishbar.org> wrote:
> Hi,
>
> On 24 March 2015 at 16:07, Gerd Hoffmann <kraxel@redhat.com> wrote:
>> +static int virtio_gpu_crtc_page_flip(struct drm_crtc *crtc,
>> +                                    struct drm_framebuffer *fb,
>> +                                    struct drm_pending_vblank_event *event,
>> +                                    uint32_t flags)
>> +{
>> +       return -EINVAL;
>> +}
>
> I'm not going to lie, I was really hoping the 5th (?) GPU option for
> Qemu would support pageflipping. Daniel's comment about conversion to
> atomic is relevant, but: do you have a mechanism which allows you to
> post updates (e.g. 'start displaying this buffer now please') that
> allows you to get events back when they have actually been displayed?

Page flip is implemented in a later patch,

https://www.kraxel.org/cgit/linux/commit/?h=virtio-gpu&id=1e167e8e964f8e08100d315dd354cc0a4b090841

Since its a long way from an actual display, finding out when
something is actually displayed is hard,
but when we've posted it to the frontbuffer should be fine.

Dave.