[RFC PATCH v3 0/4] Deliver vGPU display vblank event to userspace

[Gerd Hoffmann]

  Hi,

> Instead of delivering page flip events, we choose to post display vblank
> event. Handling page flip events for both primary plane and cursor plane
> may make user space quite busy, although we have the mask/unmask mechansim
> for mitigation. Besides, there are some cases that guest app only uses
> one framebuffer for both drawing and display. In such case, guest OS won't
> do the plane page flip when the framebuffer is updated, thus the user
> land won't be notified about the updated framebuffer.

What happens when the guest is idle and doesn't draw anything to the
framebuffer?

cheers,
  Gerd