drm/i915: Retry execbuffer pinning after clearing the GTT

If we fail to pin all of the buffers in an execbuffer request, go through
and clear the GTT and try again to see if its just a matter of fragmentation
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/i915/i915_gem.c

@@ -1087,6 +1087,19 @@ i915_gem_evict_something(struct drm_device *dev)
 	return ret;
 }
 
+static int
+i915_gem_evict_everything(struct drm_device *dev)
+{
+	int ret;
+
+	for (;;) {
+		ret = i915_gem_evict_something(dev);
+		if (ret != 0)
+			break;
+	}
+	return ret;
+}
+
 static int
 i915_gem_object_get_page_list(struct drm_gem_object *obj)
 {
@@ -1173,6 +1186,7 @@ i915_gem_object_bind_to_gtt(struct drm_gem_object *obj, unsigned alignment)
 
 		ret = i915_gem_evict_something(dev);
 		if (ret != 0) {
+			if (ret != -ERESTARTSYS)
 				DRM_ERROR("Failed to evict a buffer %d\n", ret);
 			return ret;
 		}
@@ -1922,6 +1936,7 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
 	int ret, i, pinned = 0;
 	uint64_t exec_offset;
 	uint32_t seqno, flush_domains;
+	int pin_tries;
 
 #if WATCH_EXEC
 	DRM_INFO("buffers_ptr %d buffer_count %d len %08x\n",
@@ -1970,7 +1985,7 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
 		return -EBUSY;
 	}
 
-	/* Look up object handles and perform the relocations */
+	/* Look up object handles */
 	for (i = 0; i < args->buffer_count; i++) {
 		object_list[i] = drm_gem_object_lookup(dev, file_priv,
 						       exec_list[i].handle);
@@ -1980,17 +1995,39 @@ i915_gem_execbuffer(struct drm_device *dev, void *data,
 			ret = -EBADF;
 			goto err;
 		}
+	}
 
+	/* Pin and relocate */
+	for (pin_tries = 0; ; pin_tries++) {
+		ret = 0;
+		for (i = 0; i < args->buffer_count; i++) {
 			object_list[i]->pending_read_domains = 0;
 			object_list[i]->pending_write_domain = 0;
 			ret = i915_gem_object_pin_and_relocate(object_list[i],
 							       file_priv,
 							       &exec_list[i]);
-		if (ret) {
-			DRM_ERROR("object bind and relocate failed %d\n", ret);
+			if (ret)
+				break;
+			pinned = i + 1;
+		}
+		/* success */
+		if (ret == 0)
+			break;
+
+		/* error other than GTT full, or we've already tried again */
+		if (ret != -ENOMEM || pin_tries >= 1) {
+			DRM_ERROR("Failed to pin buffers %d\n", ret);
 			goto err;
 		}
-		pinned = i + 1;
+
+		/* unpin all of our buffers */
+		for (i = 0; i < pinned; i++)
+			i915_gem_object_unpin(object_list[i]);
+
+		/* evict everyone we can from the aperture */
+		ret = i915_gem_evict_everything(dev);
+		if (ret)
+			goto err;
 	}
 
 	/* Set the pending read domains for the batch buffer to COMMAND */