Revert "nouveau: rip out busy fence waits"

This reverts commit d45bb9c5.

Just got a report that this causes some suspend/resume issues,
so back it out and I'll investigate it later.
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/nouveau/nouveau_bo.c

@@ -898,7 +898,7 @@ nouveau_bo_move_m2mf(struct ttm_buffer_object *bo, int evict,
 	 * Without this the operation can timeout and we'll fallback to a
 	 * software copy, which might take several minutes to finish.
 	 */
-	nouveau_fence_wait(fence, false);
+	nouveau_fence_wait(fence, false, false);
 	ret = ttm_bo_move_accel_cleanup(bo, &fence->base, evict, false,
 					new_reg);
 	nouveau_fence_unref(&fence);

drivers/gpu/drm/nouveau/nouveau_chan.c

@@ -72,7 +72,7 @@ nouveau_channel_idle(struct nouveau_channel *chan)
 
 		ret = nouveau_fence_new(&fence, chan);
 		if (!ret) {
-			ret = nouveau_fence_wait(fence, false);
+			ret = nouveau_fence_wait(fence, false, false);
 			nouveau_fence_unref(&fence);
 		}
 

drivers/gpu/drm/nouveau/nouveau_dmem.c

@@ -128,7 +128,7 @@ static void nouveau_dmem_page_free(struct page *page)
 static void nouveau_dmem_fence_done(struct nouveau_fence **fence)
 {
 	if (fence) {
-		nouveau_fence_wait(*fence, false);
+		nouveau_fence_wait(*fence, true, false);
 		nouveau_fence_unref(fence);
 	} else {
 		/*

drivers/gpu/drm/nouveau/nouveau_fence.c

@@ -311,11 +311,39 @@ nouveau_fence_wait_legacy(struct dma_fence *f, bool intr, long wait)
 	return timeout - t;
 }
 
+static int
+nouveau_fence_wait_busy(struct nouveau_fence *fence, bool intr)
+{
+	int ret = 0;
+
+	while (!nouveau_fence_done(fence)) {
+		if (time_after_eq(jiffies, fence->timeout)) {
+			ret = -EBUSY;
+			break;
+		}
+
+		__set_current_state(intr ?
+				    TASK_INTERRUPTIBLE :
+				    TASK_UNINTERRUPTIBLE);
+
+		if (intr && signal_pending(current)) {
+			ret = -ERESTARTSYS;
+			break;
+		}
+	}
+
+	__set_current_state(TASK_RUNNING);
+	return ret;
+}
+
 int
-nouveau_fence_wait(struct nouveau_fence *fence, bool intr)
+nouveau_fence_wait(struct nouveau_fence *fence, bool lazy, bool intr)
 {
 	long ret;
 
+	if (!lazy)
+		return nouveau_fence_wait_busy(fence, intr);
+
 	ret = dma_fence_wait_timeout(&fence->base, intr, 15 * HZ);
 	if (ret < 0)
 		return ret;

drivers/gpu/drm/nouveau/nouveau_fence.h

@@ -23,7 +23,7 @@ void nouveau_fence_unref(struct nouveau_fence **);
 
 int  nouveau_fence_emit(struct nouveau_fence *);
 bool nouveau_fence_done(struct nouveau_fence *);
-int  nouveau_fence_wait(struct nouveau_fence *, bool intr);
+int  nouveau_fence_wait(struct nouveau_fence *, bool lazy, bool intr);
 int  nouveau_fence_sync(struct nouveau_bo *, struct nouveau_channel *, bool exclusive, bool intr);
 
 struct nouveau_fence_chan {

drivers/gpu/drm/nouveau/nouveau_gem.c

@@ -928,7 +928,7 @@ nouveau_gem_ioctl_pushbuf(struct drm_device *dev, void *data,
 	}
 
 	if (sync) {
-		if (!(ret = nouveau_fence_wait(fence, false))) {
+		if (!(ret = nouveau_fence_wait(fence, false, false))) {
 			if ((ret = dma_fence_get_status(&fence->base)) == 1)
 				ret = 0;
 		}