drm/i915: Serialise presentation with imported dmabufs

obj->base.dma_buf represents a dma-buf exported from this object (for
use by others). On the contrary, obj->base.import_attach represents the
source dma-buf that was used to create this object (if any). When
serialising with third parties, we need to wait on their rendering via
the import attachment as well as their rendering on our exported
dma-buf.

v2: Wait on both import and export.
v3: Rebase

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Alex Goins <agoins@nvidia.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Alex Goins <agoins@nvidia.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1466148527-10891-1-git-send-email-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem_dmabuf.h

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2016 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+#ifndef _I915_GEM_DMABUF_H_
+#define _I915_GEM_DMABUF_H_
+
+#include <linux/dma-buf.h>
+
+static inline struct reservation_object *
+i915_gem_object_get_dmabuf_resv(struct drm_i915_gem_object *obj)
+{
+	struct dma_buf *dma_buf;
+
+	if (obj->base.dma_buf)
+		dma_buf = obj->base.dma_buf;
+	else if (obj->base.import_attach)
+		dma_buf = obj->base.import_attach->dmabuf;
+	else
+		return NULL;
+
+	return dma_buf->resv;
+}
+
+#endif

drivers/gpu/drm/i915/intel_display.c

@@ -36,6 +36,7 @@
 #include "intel_drv.h"
 #include <drm/i915_drm.h>
 #include "i915_drv.h"
+#include "i915_gem_dmabuf.h"
 #include "intel_dsi.h"
 #include "i915_trace.h"
 #include <drm/drm_atomic.h>
@@ -46,7 +47,6 @@
 #include <drm/drm_rect.h>
 #include <linux/dma_remapping.h>
 #include <linux/reservation.h>
-#include <linux/dma-buf.h>
 
 static bool is_mmio_work(struct intel_flip_work *work)
 {
@@ -11429,6 +11429,8 @@ static int intel_gen7_queue_flip(struct drm_device *dev,
 static bool use_mmio_flip(struct intel_engine_cs *engine,
 			  struct drm_i915_gem_object *obj)
 {
+	struct reservation_object *resv;
+
 	/*
 	 * This is not being used for older platforms, because
 	 * non-availability of flip done interrupt forces us to use
@@ -11449,12 +11451,12 @@ static bool use_mmio_flip(struct intel_engine_cs *engine,
 		return true;
 	else if (i915.enable_execlists)
 		return true;
-	else if (obj->base.dma_buf &&
-		 !reservation_object_test_signaled_rcu(obj->base.dma_buf->resv,
-						       false))
+
+	resv = i915_gem_object_get_dmabuf_resv(obj);
+	if (resv && !reservation_object_test_signaled_rcu(resv, false))
 		return true;
-	else
-		return engine != i915_gem_request_get_engine(obj->last_write_req);
+
+	return engine != i915_gem_request_get_engine(obj->last_write_req);
 }
 
 static void skl_do_mmio_flip(struct intel_crtc *intel_crtc,
@@ -11543,6 +11545,7 @@ static void intel_mmio_flip_work_func(struct work_struct *w)
 	struct intel_framebuffer *intel_fb =
 		to_intel_framebuffer(crtc->base.primary->fb);
 	struct drm_i915_gem_object *obj = intel_fb->obj;
+	struct reservation_object *resv;
 
 	if (work->flip_queued_req)
 		WARN_ON(__i915_wait_request(work->flip_queued_req,
@@ -11550,9 +11553,9 @@ static void intel_mmio_flip_work_func(struct work_struct *w)
 					    &dev_priv->rps.mmioflips));
 
 	/* For framebuffer backed by dmabuf, wait for fence */
-	if (obj->base.dma_buf)
-		WARN_ON(reservation_object_wait_timeout_rcu(obj->base.dma_buf->resv,
-							    false, false,
+	resv = i915_gem_object_get_dmabuf_resv(obj);
+	if (resv)
+		WARN_ON(reservation_object_wait_timeout_rcu(resv, false, false,
 							    MAX_SCHEDULE_TIMEOUT) < 0);
 
 	intel_pipe_update_start(crtc);
@@ -14032,6 +14035,7 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 	struct drm_framebuffer *fb = new_state->fb;
 	struct drm_i915_gem_object *obj = intel_fb_obj(fb);
 	struct drm_i915_gem_object *old_obj = intel_fb_obj(plane->state->fb);
+	struct reservation_object *resv;
 	int ret = 0;
 
 	if (!obj && !old_obj)
@@ -14061,12 +14065,15 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 		}
 	}
 
+	if (!obj)
+		return 0;
+
 	/* For framebuffer backed by dmabuf, wait for fence */
-	if (obj && obj->base.dma_buf) {
+	resv = i915_gem_object_get_dmabuf_resv(obj);
+	if (resv) {
 		long lret;
 
-		lret = reservation_object_wait_timeout_rcu(obj->base.dma_buf->resv,
-							   false, true,
+		lret = reservation_object_wait_timeout_rcu(resv, false, true,
 							   MAX_SCHEDULE_TIMEOUT);
 		if (lret == -ERESTARTSYS)
 			return lret;
@@ -14074,9 +14081,7 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 		WARN(lret < 0, "waiting returns %li\n", lret);
 	}
 
-	if (!obj) {
-		ret = 0;
-	} else if (plane->type == DRM_PLANE_TYPE_CURSOR &&
+	if (plane->type == DRM_PLANE_TYPE_CURSOR &&
 	    INTEL_INFO(dev)->cursor_needs_physical) {
 		int align = IS_I830(dev) ? 16 * 1024 : 256;
 		ret = i915_gem_object_attach_phys(obj, align);
@@ -14086,7 +14091,7 @@ intel_prepare_plane_fb(struct drm_plane *plane,
 		ret = intel_pin_and_fence_fb_obj(fb, new_state->rotation);
 	}
 
-	if (ret == 0 && obj) {
+	if (ret == 0) {
 		struct intel_plane_state *plane_state =
 			to_intel_plane_state(new_state);