Re: [PATCH] Add virtio gpu driver.

On 25 March 2015 at 08:50, Daniel Stone [off-list ref] wrote:

Hi,

On 24 March 2015 at 16:07, Gerd Hoffmann [off-list ref] wrote:

quoted

+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.