[PATCH v3 0/4] Use no_vblank property for drivers without VBLANK

[Gerd Hoffmann]

On Mon, Jan 20, 2020 at 01:20:47PM +0100, Thomas Zimmermann wrote:
> Instead of faking VBLANK events by themselves, drivers without VBLANK
> support can enable drm_crtc_vblank.no_vblank and let DRM do the rest.
> The patchset makes this official and converts over drivers.
> 
> The current implementation looks at the number of initialized CRTCs
> wrt vblanking. If vblanking has been initialized for a CRTC, the driver
> is responsible for sending out VBLANK events. Otherwise, DRM will send
> out the event. The behaviour selected by initializing no_vblank as part
> of drm_atomic_helper_check_modeset().
> 
> I went through all drivers, looking for those that call send out VBLANK
> events but do not call drm_vblank_init(). These are converted to the new
> semantics. This affects tiny drivers; drivers for virtual hardware; and
> a few others, which do not support interrupts. Xen comes with its
> own VBLANK logic and disables no_vblank explictly.

Acked-by: Gerd Hoffmann <kraxel at redhat.com>