drm: omapdrm: Keep vblank interrupt enabled while CRTC is active

Instead of going through a complicated private IRQ registration
mechanism, handle the vblank interrupt activation with the standard
drm_crtc_vblank_get() and drm_crtc_vblank_put() mechanism. This will let
the DRM core keep the vblank interrupt enabled as long as needed to
update the frame counter.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/omapdrm/omap_crtc.c

@@ -36,8 +36,6 @@ struct omap_crtc {
 
 	struct videomode vm;
 
-	struct omap_drm_irq vblank_irq;
-
 	bool ignore_digit_sync_lost;
 
 	bool enabled;
@@ -275,22 +273,6 @@ static const struct dss_mgr_ops mgr_ops = {
  * Setup, Flush and Page Flip
  */
 
-static void omap_crtc_complete_page_flip(struct drm_crtc *crtc)
-{
-	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
-	struct drm_pending_vblank_event *event;
-	struct drm_device *dev = crtc->dev;
-	unsigned long flags;
-
-	spin_lock_irqsave(&dev->event_lock, flags);
-	event = omap_crtc->event;
-	omap_crtc->event = NULL;
-
-	if (event)
-		drm_crtc_send_vblank_event(crtc, event);
-	spin_unlock_irqrestore(&dev->event_lock, flags);
-}
-
 void omap_crtc_error_irq(struct drm_crtc *crtc, uint32_t irqstatus)
 {
 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
@@ -304,30 +286,38 @@ void omap_crtc_error_irq(struct drm_crtc *crtc, uint32_t irqstatus)
 	DRM_ERROR_RATELIMITED("%s: errors: %08x\n", omap_crtc->name, irqstatus);
 }
 
-static void omap_crtc_vblank_irq(struct omap_drm_irq *irq, uint32_t irqstatus)
+void omap_crtc_vblank_irq(struct drm_crtc *crtc)
 {
-	struct omap_crtc *omap_crtc =
-			container_of(irq, struct omap_crtc, vblank_irq);
-	struct drm_device *dev = omap_crtc->base.dev;
-	struct drm_crtc *crtc = &omap_crtc->base;
+	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
+	bool pending;
 
-	if (dispc_mgr_go_busy(omap_crtc->channel))
+	spin_lock(&crtc->dev->event_lock);
+	/*
+	 * If the dispc is busy we're racing the flush operation. Try again on
+	 * the next vblank interrupt.
+	 */
+	if (dispc_mgr_go_busy(omap_crtc->channel)) {
+		spin_unlock(&crtc->dev->event_lock);
 		return;
+	}
 
-	DBG("%s: apply done", omap_crtc->name);
-
-	__omap_irq_unregister(dev, &omap_crtc->vblank_irq);
+	/* Send the vblank event if one has been requested. */
+	if (omap_crtc->event) {
+		drm_crtc_send_vblank_event(crtc, omap_crtc->event);
+		omap_crtc->event = NULL;
+	}
 
-	spin_lock(&crtc->dev->event_lock);
-	WARN_ON(!omap_crtc->pending);
+	pending = omap_crtc->pending;
 	omap_crtc->pending = false;
 	spin_unlock(&crtc->dev->event_lock);
 
-	/* wake up userspace */
-	omap_crtc_complete_page_flip(&omap_crtc->base);
+	if (pending)
+		drm_crtc_vblank_put(crtc);
 
-	/* wake up omap_atomic_complete */
+	/* Wake up omap_atomic_complete. */
 	wake_up(&omap_crtc->pending_wait);
+
+	DBG("%s: apply done", omap_crtc->name);
 }
 
 /* -----------------------------------------------------------------------------
@@ -340,8 +330,6 @@ static void omap_crtc_destroy(struct drm_crtc *crtc)
 
 	DBG("%s", omap_crtc->name);
 
-	WARN_ON(omap_crtc->vblank_irq.registered);
-
 	drm_crtc_cleanup(crtc);
 
 	kfree(omap_crtc);
@@ -350,17 +338,18 @@ static void omap_crtc_destroy(struct drm_crtc *crtc)
 static void omap_crtc_enable(struct drm_crtc *crtc)
 {
 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
+	int ret;
 
 	DBG("%s", omap_crtc->name);
 
 	spin_lock_irq(&crtc->dev->event_lock);
+	drm_crtc_vblank_on(crtc);
+	ret = drm_crtc_vblank_get(crtc);
+	WARN_ON(ret != 0);
+
 	WARN_ON(omap_crtc->pending);
 	omap_crtc->pending = true;
 	spin_unlock_irq(&crtc->dev->event_lock);
-
-	omap_irq_register(crtc->dev, &omap_crtc->vblank_irq);
-
-	drm_crtc_vblank_on(crtc);
 }
 
 static void omap_crtc_disable(struct drm_crtc *crtc)
@@ -413,8 +402,7 @@ static void omap_crtc_atomic_flush(struct drm_crtc *crtc,
 				   struct drm_crtc_state *old_crtc_state)
 {
 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
-
-	WARN_ON(omap_crtc->vblank_irq.registered);
+	int ret;
 
 	if (crtc->state->color_mgmt_changed) {
 		struct drm_color_lut *lut = NULL;
@@ -441,16 +429,18 @@ static void omap_crtc_atomic_flush(struct drm_crtc *crtc,
 
 	DBG("%s: GO", omap_crtc->name);
 
+	ret = drm_crtc_vblank_get(crtc);
+	WARN_ON(ret != 0);
+
 	spin_lock_irq(&crtc->dev->event_lock);
+	dispc_mgr_go(omap_crtc->channel);
+
 	WARN_ON(omap_crtc->pending);
 	omap_crtc->pending = true;
 
 	if (crtc->state->event)
 		omap_crtc->event = crtc->state->event;
 	spin_unlock_irq(&crtc->dev->event_lock);
-
-	dispc_mgr_go(omap_crtc->channel);
-	omap_irq_register(crtc->dev, &omap_crtc->vblank_irq);
 }
 
 static bool omap_crtc_is_plane_prop(struct drm_crtc *crtc,
@@ -571,9 +561,6 @@ struct drm_crtc *omap_crtc_init(struct drm_device *dev,
 	omap_crtc->channel = channel;
 	omap_crtc->name = channel_names[channel];
 
-	omap_crtc->vblank_irq.irqmask = pipe2vbl(crtc);
-	omap_crtc->vblank_irq.irq = omap_crtc_vblank_irq;
-
 	ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
 					&omap_crtc_funcs, NULL);
 	if (ret < 0) {

drivers/gpu/drm/omapdrm/omap_drv.h

@@ -155,6 +155,7 @@ struct drm_crtc *omap_crtc_init(struct drm_device *dev,
 		struct drm_plane *plane, enum omap_channel channel, int id);
 int omap_crtc_wait_pending(struct drm_crtc *crtc);
 void omap_crtc_error_irq(struct drm_crtc *crtc, uint32_t irqstatus);
+void omap_crtc_vblank_irq(struct drm_crtc *crtc);
 
 struct drm_plane *omap_plane_init(struct drm_device *dev,
 		int id, enum drm_plane_type type,

drivers/gpu/drm/omapdrm/omap_irq.c

@@ -245,8 +245,10 @@ static irqreturn_t omap_irq_handler(int irq, void *arg)
 		struct drm_crtc *crtc = priv->crtcs[id];
 		enum omap_channel channel = omap_crtc_channel(crtc);
 
-		if (irqstatus & pipe2vbl(crtc))
+		if (irqstatus & pipe2vbl(crtc)) {
 			drm_handle_vblank(dev, id);
+			omap_crtc_vblank_irq(crtc);
+		}
 
 		if (irqstatus & dispc_mgr_get_sync_lost_irq(channel))
 			omap_crtc_error_irq(crtc, irqstatus);