drm/udl: Implement page_flip ioctl

This is a very crude page_flip implementation for UDL. There are ways
to make it better (make it asynchronous, make it do actual vsynced
flips...) but that's for another patch.

[airlied: fixup primary change]
Signed-off-by: Stéphane Marchesin <marcheu@chromium.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/udl/udl_modeset.c

@@ -363,6 +363,26 @@ static void udl_crtc_destroy(struct drm_crtc *crtc)
 	kfree(crtc);
 }
 
+static int udl_crtc_page_flip(struct drm_crtc *crtc,
+			      struct drm_framebuffer *fb,
+			      struct drm_pending_vblank_event *event,
+			      uint32_t page_flip_flags)
+{
+	struct udl_framebuffer *ufb = to_udl_fb(fb);
+	struct drm_device *dev = crtc->dev;
+	unsigned long flags;
+
+	udl_handle_damage(ufb, 0, 0, fb->width, fb->height);
+
+	spin_lock_irqsave(&dev->event_lock, flags);
+	if (event)
+		drm_send_vblank_event(dev, 0, event);
+	spin_unlock_irqrestore(&dev->event_lock, flags);
+	crtc->primary->fb = fb;
+
+	return 0;
+}
+
 static void udl_crtc_prepare(struct drm_crtc *crtc)
 {
 }
@@ -384,6 +404,7 @@ static struct drm_crtc_helper_funcs udl_helper_funcs = {
 static const struct drm_crtc_funcs udl_crtc_funcs = {
 	.set_config = drm_crtc_helper_set_config,
 	.destroy = udl_crtc_destroy,
+	.page_flip = udl_crtc_page_flip,
 };
 
 static int udl_crtc_init(struct drm_device *dev)