[PATCH 2/2] drm/i915: Handle dma fences in dirtyfb callback

[Jouni Högander]

Take into account dma fences in dirtyfb callback. If there is no
unsignaled dma fences perform flush immediately. If there are
unsignaled dma fences perform invalidate and add callback which will
queue flush when the fence gets signaled.

Signed-off-by: Jouni Högander <jouni.hogander at intel.com>
---
 drivers/gpu/drm/i915/display/intel_fb.c | 53 +++++++++++++++++++++++--
 1 file changed, 50 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_fb.c b/drivers/gpu/drm/i915/display/intel_fb.c
index e5f637897b5e..dbbd9a857367 100644
--- a/drivers/gpu/drm/i915/display/intel_fb.c
+++ b/drivers/gpu/drm/i915/display/intel_fb.c
@@ -7,6 +7,9 @@
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_modeset_helper.h>
 
+#include <linux/dma-fence.h>
+#include <linux/dma-resv.h>
+
 #include "i915_drv.h"
 #include "intel_display.h"
 #include "intel_display_types.h"
@@ -1854,6 +1857,20 @@ static int intel_user_framebuffer_create_handle(struct drm_framebuffer *fb,
 	return drm_gem_handle_create(file, &obj->base, handle);
 }
 
+struct frontbuffer_fence_cb {
+	struct dma_fence_cb base;
+	struct intel_frontbuffer *front;
+};
+
+static void intel_user_framebuffer_fence_wake(struct dma_fence *dma,
+				   struct dma_fence_cb *data)
+{
+	struct frontbuffer_fence_cb *cb = container_of(data, typeof(*cb), base);
+
+	intel_frontbuffer_queue_flush(cb->front);
+	kfree(cb);
+}
+
 static int intel_user_framebuffer_dirty(struct drm_framebuffer *fb,
 					struct drm_file *file,
 					unsigned int flags, unsigned int color,
@@ -1861,11 +1878,41 @@ static int intel_user_framebuffer_dirty(struct drm_framebuffer *fb,
 					unsigned int num_clips)
 {
 	struct drm_i915_gem_object *obj = intel_fb_obj(fb);
+	struct dma_resv_iter cursor;
+	struct dma_fence *fence;
+	int ret;
 
-	i915_gem_object_flush_if_display(obj);
-	intel_frontbuffer_flush(to_intel_frontbuffer(fb), ORIGIN_DIRTYFB);
+	if (dma_resv_test_signaled(obj->base.resv, dma_resv_usage_rw(false))) {
+		i915_gem_object_flush_if_display(obj);
+		intel_frontbuffer_flush(to_intel_frontbuffer(fb),
+					ORIGIN_DIRTYFB);
+		return 0;
+	}
 
-	return 0;
+	intel_frontbuffer_invalidate(to_intel_frontbuffer(fb), ORIGIN_DIRTYFB);
+
+	dma_resv_iter_begin(&cursor, obj->base.resv, dma_resv_usage_rw(false));
+	dma_resv_for_each_fence_unlocked(&cursor, fence) {
+		struct frontbuffer_fence_cb *cb = kmalloc(
+			sizeof(struct frontbuffer_fence_cb), GFP_KERNEL);
+		if (!cb) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		ret = dma_fence_add_callback(fence, &cb->base,
+					     intel_user_framebuffer_fence_wake);
+		if (ret) {
+			intel_user_framebuffer_fence_wake(fence, &cb->base);
+			if (ret == -ENOENT)
+				ret = 0;
+			else
+				break;
+		}
+	}
+	dma_resv_iter_end(&cursor);
+
+	return ret;
 }
 
 static const struct drm_framebuffer_funcs intel_fb_funcs = {
-- 
2.34.1