drm/virtgio: Send flip event based on backend setting

Cache out fences in atomic commit and signal them when the backend asks to. The backend is supposed to send to frontend the number of fences to signal when the backend presents a frame to users. Only in this way we can preserve the semantics of present fence. Tracked-On: OAM-128370 Signed-off-by: hangliu1 <[email protected]> Signed-off-by: Weifeng Liu <[email protected]>
projectceladon · Dec 10, 2024 · 86d17c8 · 86d17c8
1 parent e4c7a16
commit 86d17c8
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Showing 3 changed files with 48 additions and 9 deletions.
diff --git a/drivers/gpu/drm/virtio/virtgpu_display.c b/drivers/gpu/drm/virtio/virtgpu_display.c
@@ -161,18 +161,37 @@ static void virtio_gpu_crtc_atomic_flush(struct drm_crtc *crtc,
 	struct virtio_gpu_output *output = drm_crtc_to_virtio_gpu_output(crtc);
 	struct drm_device *drm = crtc->dev;
 	struct virtio_gpu_device *vgdev = drm->dev_private;
+	int i;
 
-	if(vgdev->has_vblank) {
-		if (crtc->state->event) {
-			spin_lock_irq(&drm->event_lock);
-			if (drm_crtc_vblank_get(crtc) != 0)
-				drm_crtc_send_vblank_event(crtc, crtc->state->event);
-			else
-				drm_crtc_arm_vblank_event(crtc, crtc->state->event);
-			spin_unlock_irq(&drm->event_lock);
+	if (vgdev->has_vblank && crtc->state->event) {
+		spin_lock_irq(&drm->event_lock);
+		if (drm_crtc_vblank_get(crtc) != 0) {
+			// Cannot enable vblank, send it right now.
+			drm_crtc_send_vblank_event(crtc, crtc->state->event);
+			crtc->state->event = NULL;
+		} else {
+			for (i = 0; i < VBLANK_EVENT_CACHE_SIZE; i++) {
+				if (vgdev->cache_event[i] == NULL) {
+					break;
+				}
+			}
+			if (i == VBLANK_EVENT_CACHE_SIZE) {
+				// Cache is full, empty it cache or the system
+				// gets huang.
+				for (i = 0; i < VBLANK_EVENT_CACHE_SIZE; i++) {
+					if (vgdev->cache_event[i] != NULL) {
+						drm_crtc_send_vblank_event(crtc, vgdev->cache_event[i]);
+						vgdev->cache_event[i] = NULL;
+					}
+				}
+				i = 0;
+			}
+			vgdev->cache_event[i] = crtc->state->event;
 			crtc->state->event = NULL;
 		}
+		spin_unlock_irq(&drm->event_lock);
 	}
+
 	if(vgdev->has_multi_plane)
 		virtio_gpu_resource_flush_sync(crtc);
 

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -180,6 +180,9 @@ struct virtio_gpu_vbuffer {
 #define VIRTIO_GPU_MAX_PLANES 6
 /*hardcode igpu scaler number ver>11 */
 #define SKL_NUM_SCALERS 2
+
+#define VBLANK_EVENT_CACHE_SIZE	3
+
 struct virtio_gpu_output {
 	int index;
 	struct drm_crtc crtc;
@@ -238,6 +241,7 @@ struct virtio_gpu_device {
 	struct virtio_device *vdev;
 
 	struct virtio_gpu_output outputs[VIRTIO_GPU_MAX_SCANOUTS];
+	struct drm_pending_vblank_event *cache_event[VBLANK_EVENT_CACHE_SIZE];
 	uint32_t num_scanouts;
 	uint32_t num_vblankq;
 	struct virtio_gpu_queue ctrlq;

diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -100,7 +100,7 @@ void virtio_gpu_vblank_ack(struct virtqueue *vq)
 	unsigned long irqflags;
 	unsigned int len;
 	unsigned int *ret_value;
-	int target = 0;
+	int target = 0, i, curr = 0;
 
 	while((target < vgdev->num_vblankq) && (vgdev->vblank[target].vblank.vq != vq)) {
 		target++;
@@ -115,6 +115,22 @@ void virtio_gpu_vblank_ack(struct virtqueue *vq)
 	spin_unlock_irqrestore(&vgdev->vblank[target].vblank.qlock, irqflags);
 	drm_handle_vblank(dev, target);
 
+	spin_lock_irqsave(&dev->event_lock, irqflags);
+	for (i = 0; i < VBLANK_EVENT_CACHE_SIZE; i++) {
+		if (vgdev->cache_event[i]) {
+			if (i < *ret_value) {
+				drm_crtc_send_vblank_event(&vgdev->outputs[target].crtc,
+							vgdev->cache_event[i]);
+				vgdev->cache_event[i] = NULL;
+			}
+		}
+	}
+
+	for (i = 0; i < VBLANK_EVENT_CACHE_SIZE; ++i)
+		if (vgdev->cache_event[i])
+			vgdev->cache_event[curr++] = vgdev->cache_event[i];
+
+	spin_unlock_irqrestore(&dev->event_lock, irqflags);
 }
 
 void virtio_gpu_cursor_ack(struct virtqueue *vq)