Re: [PATCH] Add virtio gpu driver.

[Gerd Hoffmann <kraxel@redhat.com>]

  Hi,

> - add a small core function to registerr HOT_X/HOT_Y for a (cursor) plane,
>   e.g. drm_plane_register_hotspot(). That should allocate the properties
>   (if they don't exist yet) and then attach those props to the cursor. We
>   don't want those props everywhere, but only on drivers that support/need
>   them, aka virtual hw.

Hmm, why is this special to virtual hw?

>  	if (crtc->cursor) {
> -		ret = drm_mode_cursor_universal(crtc, req, file_priv);
> +		if (drm_core_check_feature(DRIVER_ATOMIC))
> +			ret = drm_mode_cursor_atomic(crtc, req, file_priv);
> +		else
> +			ret = drm_mode_cursor_universal(crtc, req, file_priv);
>  		goto out;

>   drm_mode_cursor_atomic would simply be a fusing of
>   drm_mode_cursor_universal + drm_atomic_helper_update_plane (dump all the
>   intermediate variables and store directly in the plane state), with the
>   addition of also storing hot_x/y into the plane state.

Hmm, that'll either make drm_mode_cursor_atomic a big cut+pasted
function, or need quite some refactoring to move common code into
functions callable from both drm_mode_cursor_atomic
+drm_mode_cursor_universal ...

Why attach the hotspot to the plane?  Wouldn't it make more sense to
make it a framebuffer property?

cheers,
  Gerd