diff --git a/nouveau/abi16.c b/nouveau/abi16.c
index 59bc436..44fda64 100644
--- a/nouveau/abi16.c
+++ b/nouveau/abi16.c
@@ -32,8 +32,10 @@
 
 #include "private.h"
 
+#include "nvif/class.h"
 
-drm_private int
+
+static int
 abi16_chan_nv04(struct nouveau_object *obj)
 {
 	struct nouveau_device *dev = (struct nouveau_device *)obj->parent;
@@ -57,7 +59,7 @@
 	return 0;
 }
 
-drm_private int
+static int
 abi16_chan_nvc0(struct nouveau_object *obj)
 {
 	struct nouveau_device *dev = (struct nouveau_device *)obj->parent;
@@ -78,7 +80,7 @@
 	return 0;
 }
 
-drm_private int
+static int
 abi16_chan_nve0(struct nouveau_object *obj)
 {
 	struct nouveau_device *dev = (struct nouveau_device *)obj->parent;
@@ -104,7 +106,7 @@
 	return 0;
 }
 
-drm_private int
+static int
 abi16_engobj(struct nouveau_object *obj)
 {
 	struct drm_nouveau_grobj_alloc req = {
@@ -115,6 +117,27 @@
 	struct nouveau_device *dev;
 	int ret;
 
+	/* Older kernel versions did not have the concept of nouveau-
+	 * specific classes and abused some NVIDIA-assigned ones for
+	 * a SW class.  The ABI16 layer has compatibility in place to
+	 * translate these older identifiers to the newer ones.
+	 *
+	 * Clients that have been updated to use NVIF are required to
+	 * use the newer class identifiers, which means that they'll
+	 * break if running on an older kernel.
+	 *
+	 * To handle this case, when using ABI16, we translate to the
+	 * older values which work on any kernel.
+	 */
+	switch (req.class) {
+	case NVIF_CLASS_SW_NV04 : req.class = 0x006e; break;
+	case NVIF_CLASS_SW_NV10 : req.class = 0x016e; break;
+	case NVIF_CLASS_SW_NV50 : req.class = 0x506e; break;
+	case NVIF_CLASS_SW_GF100: req.class = 0x906e; break;
+	default:
+		break;
+	}
+
 	dev = nouveau_object_find(obj, NOUVEAU_DEVICE_CLASS);
 	ret = drmCommandWrite(dev->fd, DRM_NOUVEAU_GROBJ_ALLOC,
 			      &req, sizeof(req));
@@ -125,7 +148,7 @@
 	return 0;
 }
 
-drm_private int
+static int
 abi16_ntfy(struct nouveau_object *obj)
 {
 	struct nv04_notify *ntfy = obj->data;
@@ -149,6 +172,61 @@
 }
 
 drm_private void
+abi16_delete(struct nouveau_object *obj)
+{
+	struct nouveau_device *dev =
+		nouveau_object_find(obj, NOUVEAU_DEVICE_CLASS);
+	if (obj->oclass == NOUVEAU_FIFO_CHANNEL_CLASS) {
+		struct drm_nouveau_channel_free req;
+		req.channel = obj->handle;
+		drmCommandWrite(dev->fd, DRM_NOUVEAU_CHANNEL_FREE,
+				&req, sizeof(req));
+	} else {
+		struct drm_nouveau_gpuobj_free req;
+		req.channel = obj->parent->handle;
+		req.handle  = obj->handle;
+		drmCommandWrite(dev->fd, DRM_NOUVEAU_GPUOBJ_FREE,
+				&req, sizeof(req));
+	}
+}
+
+drm_private bool
+abi16_object(struct nouveau_object *obj, int (**func)(struct nouveau_object *))
+{
+	struct nouveau_object *parent = obj->parent;
+
+	/* nouveau_object::length is (ab)used to determine whether the
+	 * object is a legacy object (!=0), or a real NVIF object.
+	 */
+	if ((parent->length != 0 && parent->oclass == NOUVEAU_DEVICE_CLASS)) {
+		if (obj->oclass == NOUVEAU_FIFO_CHANNEL_CLASS) {
+			struct nouveau_device *dev = (void *)parent;
+			if (dev->chipset < 0xc0)
+				*func = abi16_chan_nv04;
+			else
+			if (dev->chipset < 0xe0)
+				*func = abi16_chan_nvc0;
+			else
+				*func = abi16_chan_nve0;
+			return true;
+		}
+	} else
+	if ((parent->length != 0 &&
+	     parent->oclass == NOUVEAU_FIFO_CHANNEL_CLASS)) {
+		if (obj->oclass == NOUVEAU_NOTIFIER_CLASS) {
+			*func = abi16_ntfy;
+			return true;
+		}
+
+		*func = abi16_engobj;
+		return false; /* try NVIF, if supported, before calling func */
+	}
+
+	*func = NULL;
+	return false;
+}
+
+drm_private void
 abi16_bo_info(struct nouveau_bo *bo, struct drm_nouveau_gem_info *info)
 {
 	struct nouveau_bo_priv *nvbo = nouveau_bo(bo);
diff --git a/nouveau/nouveau.c b/nouveau/nouveau.c
index 97fd77b..8a0be2f 100644
--- a/nouveau/nouveau.c
+++ b/nouveau/nouveau.c
@@ -135,6 +135,7 @@
 		nvdev->gart_limit_percent = 80;
 	DRMINITLISTHEAD(&nvdev->bo_list);
 	nvdev->base.object.oclass = NOUVEAU_DEVICE_CLASS;
+	nvdev->base.object.length = ~0;
 	nvdev->base.lib_version = 0x01000000;
 	nvdev->base.chipset = chipset;
 	nvdev->base.vram_size = vram;
@@ -251,8 +252,8 @@
 		   uint32_t oclass, void *data, uint32_t length,
 		   struct nouveau_object **pobj)
 {
-	struct nouveau_device *dev;
 	struct nouveau_object *obj;
+	int (*func)(struct nouveau_object *);
 	int ret = -EINVAL;
 
 	if (length == 0)
@@ -267,37 +268,9 @@
 		memcpy(obj->data, data, length);
 	*(struct nouveau_object **)obj->data = obj;
 
-	dev = nouveau_object_find(obj, NOUVEAU_DEVICE_CLASS);
-	switch (parent->oclass) {
-	case NOUVEAU_DEVICE_CLASS:
-		switch (obj->oclass) {
-		case NOUVEAU_FIFO_CHANNEL_CLASS:
-		{
-			if (dev->chipset < 0xc0)
-				ret = abi16_chan_nv04(obj);
-			else
-			if (dev->chipset < 0xe0)
-				ret = abi16_chan_nvc0(obj);
-			else
-				ret = abi16_chan_nve0(obj);
-		}
-			break;
-		default:
-			break;
-		}
-		break;
-	case NOUVEAU_FIFO_CHANNEL_CLASS:
-		switch (obj->oclass) {
-		case NOUVEAU_NOTIFIER_CLASS:
-			ret = abi16_ntfy(obj);
-			break;
-		default:
-			ret = abi16_engobj(obj);
-			break;
-		}
-	default:
-		break;
-	}
+	abi16_object(obj, &func);
+	if (func)
+		ret = func(obj);
 
 	if (ret) {
 		free(obj);
@@ -312,24 +285,11 @@
 nouveau_object_del(struct nouveau_object **pobj)
 {
 	struct nouveau_object *obj = *pobj;
-	struct nouveau_device *dev;
 	if (obj) {
-		dev = nouveau_object_find(obj, NOUVEAU_DEVICE_CLASS);
-		if (obj->oclass == NOUVEAU_FIFO_CHANNEL_CLASS) {
-			struct drm_nouveau_channel_free req;
-			req.channel = obj->handle;
-			drmCommandWrite(dev->fd, DRM_NOUVEAU_CHANNEL_FREE,
-					&req, sizeof(req));
-		} else {
-			struct drm_nouveau_gpuobj_free req;
-			req.channel = obj->parent->handle;
-			req.handle  = obj->handle;
-			drmCommandWrite(dev->fd, DRM_NOUVEAU_GPUOBJ_FREE,
-					&req, sizeof(req));
-		}
+		abi16_delete(obj);
+		free(obj);
+		*pobj = NULL;
 	}
-	free(obj);
-	*pobj = NULL;
 }
 
 void *
diff --git a/nouveau/private.h b/nouveau/private.h
index e9439f3..5f352a4 100644
--- a/nouveau/private.h
+++ b/nouveau/private.h
@@ -114,11 +114,8 @@
 nouveau_device_open_existing(struct nouveau_device **, int, int, drm_context_t);
 
 /* abi16.c */
-drm_private int  abi16_chan_nv04(struct nouveau_object *);
-drm_private int  abi16_chan_nvc0(struct nouveau_object *);
-drm_private int  abi16_chan_nve0(struct nouveau_object *);
-drm_private int  abi16_engobj(struct nouveau_object *);
-drm_private int  abi16_ntfy(struct nouveau_object *);
+drm_private bool abi16_object(struct nouveau_object *, int (**)(struct nouveau_object *));
+drm_private void abi16_delete(struct nouveau_object *);
 drm_private void abi16_bo_info(struct nouveau_bo *, struct drm_nouveau_gem_info *);
 drm_private int  abi16_bo_init(struct nouveau_bo *, uint32_t alignment,
 			       union nouveau_bo_config *);