staging: drm/omap: send page-flip event after endwin

The endwin irq indicates that DSS has finished scanning out a buffer.
Use this to trigger page-flip event to userspace, so this happens
only *after* the previous buffer is finished.
Signed-off-by: Rob Clark <rob@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/omapdrm/omap_crtc.c

@@ -118,25 +118,21 @@ static void omap_crtc_load_lut(struct drm_crtc *crtc)
 {
 }
 
-static void page_flip_cb(void *arg)
+static void vblank_cb(void *arg)
 {
+	static uint32_t sequence = 0;
 	struct drm_crtc *crtc = arg;
 	struct drm_device *dev = crtc->dev;
 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
 	struct drm_pending_vblank_event *event = omap_crtc->event;
-	struct drm_framebuffer *old_fb = omap_crtc->old_fb;
-	struct timeval now;
 	unsigned long flags;
+	struct timeval now;
 
 	WARN_ON(!event);
 
 	omap_crtc->event = NULL;
-	omap_crtc->old_fb = NULL;
-
-	omap_crtc_mode_set_base(crtc, crtc->x, crtc->y, old_fb);
 
 	/* wakeup userspace */
-	/* TODO: this should happen *after* flip in vsync IRQ handler */
 	if (event) {
 		spin_lock_irqsave(&dev->event_lock, flags);
 		event->event.sequence = drm_vblank_count_and_time(
@@ -150,6 +146,23 @@ static void page_flip_cb(void *arg)
 	}
 }
 
+static void page_flip_cb(void *arg)
+{
+	struct drm_crtc *crtc = arg;
+	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
+	struct drm_framebuffer *old_fb = omap_crtc->old_fb;
+
+	omap_crtc->old_fb = NULL;
+
+	omap_crtc_mode_set_base(crtc, crtc->x, crtc->y, old_fb);
+
+	/* really we'd like to setup the callback atomically w/ setting the
+	 * new scanout buffer to avoid getting stuck waiting an extra vblank
+	 * cycle.. for now go for correctness and later figure out speed..
+	 */
+	omap_plane_on_endwin(omap_crtc->plane, vblank_cb, crtc);
+}
+
 static int omap_crtc_page_flip_locked(struct drm_crtc *crtc,
 		 struct drm_framebuffer *fb,
 		 struct drm_pending_vblank_event *event)

drivers/staging/omapdrm/omap_drv.h

@@ -85,6 +85,8 @@ int omap_plane_mode_set(struct drm_plane *plane,
 		unsigned int crtc_w, unsigned int crtc_h,
 		uint32_t src_x, uint32_t src_y,
 		uint32_t src_w, uint32_t src_h);
+void omap_plane_on_endwin(struct drm_plane *plane,
+		void (*fxn)(void *), void *arg);
 
 struct drm_encoder *omap_encoder_init(struct drm_device *dev,
 		struct omap_overlay_manager *mgr);

drivers/staging/omapdrm/omap_plane.c

@@ -31,6 +31,11 @@
  * plane funcs
  */
 
+struct callback {
+	void (*fxn)(void *);
+	void *arg;
+};
+
 #define to_omap_plane(x) container_of(x, struct omap_plane, base)
 
 struct omap_plane {
@@ -58,6 +63,9 @@ struct omap_plane {
 
 	/* for deferred unpin when we need to wait for scanout complete irq */
 	struct work_struct work;
+
+	/* callback on next endwin irq */
+	struct callback endwin;
 };
 
 /* map from ovl->id to the irq we are interested in for scanout-done */
@@ -84,6 +92,7 @@ static void unpin_worker(struct work_struct *work)
 {
 	struct omap_plane *omap_plane =
 			container_of(work, struct omap_plane, work);
+	struct callback endwin;
 
 	mutex_lock(&omap_plane->unpin_mutex);
 	DBG("unpinning %d of %d", omap_plane->num_unpins,
@@ -96,7 +105,28 @@ static void unpin_worker(struct work_struct *work)
 		drm_gem_object_unreference_unlocked(bo);
 		omap_plane->num_unpins--;
 	}
+	endwin = omap_plane->endwin;
+	omap_plane->endwin.fxn = NULL;
 	mutex_unlock(&omap_plane->unpin_mutex);
+
+	if (endwin.fxn)
+		endwin.fxn(endwin.arg);
+}
+
+static void install_irq(struct drm_plane *plane)
+{
+	struct omap_plane *omap_plane = to_omap_plane(plane);
+	struct omap_overlay *ovl = omap_plane->ovl;
+	int ret;
+
+	ret = omap_dispc_register_isr(dispc_isr, plane, id2irq[ovl->id]);
+
+	/*
+	 * omapdss has upper limit on # of registered irq handlers,
+	 * which we shouldn't hit.. but if we do the limit should
+	 * be raised or bad things happen:
+	 */
+	WARN_ON(ret == -EBUSY);
 }
 
 /* push changes down to dss2 */
@@ -146,17 +176,8 @@ static int commit(struct drm_plane *plane)
 		 * NOTE: really this should be atomic w/ mgr->apply() but
 		 * omapdss does not expose such an API
 		 */
-		if (omap_plane->num_unpins > 0) {
-			ret = omap_dispc_register_isr(dispc_isr,
-				plane, id2irq[ovl->id]);
-		}
-
-		/*
-		 * omapdss has upper limit on # of registered irq handlers,
-		 * which we shouldn't hit.. but if we do the limit should
-		 * be raised or bad things happen:
-		 */
-		WARN_ON(ret == -EBUSY);
+		if (omap_plane->num_unpins > 0)
+			install_irq(plane);
 
 	} else {
 		struct omap_drm_private *priv = dev->dev_private;
@@ -375,6 +396,19 @@ int omap_plane_dpms(struct drm_plane *plane, int mode)
 	return r;
 }
 
+void omap_plane_on_endwin(struct drm_plane *plane,
+		void (*fxn)(void *), void *arg)
+{
+	struct omap_plane *omap_plane = to_omap_plane(plane);
+
+	mutex_lock(&omap_plane->unpin_mutex);
+	omap_plane->endwin.fxn = fxn;
+	omap_plane->endwin.arg = arg;
+	mutex_unlock(&omap_plane->unpin_mutex);
+
+	install_irq(plane);
+}
+
 static const struct drm_plane_funcs omap_plane_funcs = {
 		.update_plane = omap_plane_update,
 		.disable_plane = omap_plane_disable,