Merge tag 'drm-misc-next-fixes-2021-02-25' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

drm-misc-next tasty fixes for v5.12:
- Cherry pick of drm-misc-fixes pull:
"here's this week's PR for drm-misc-fixes. One of the patches is a memory
leak; the rest is for hardware issues."
- Fix dt bindings for dp connector.
- Fix build error in atyfb.
- Improve error handling for dma-buf heaps.
- Make vblank timestamp more correct, by recording timestamp to be set when signaling.

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/0f60a68c-d562-7266-0815-ea75ff680b17@linux.intel.com

14 files changed, 197 insertions, 62 deletions

diff --git a/Documentation/devicetree/bindings/display/connector/dp-connector.yaml b/Documentation/devicetree/bindings/display/connector/dp-connector.yaml
index 1c17d60e776006..22792a79e7ce51 100644
--- a/Documentation/devicetree/bindings/display/connector/dp-connector.yaml
+++ b/Documentation/devicetree/bindings/display/connector/dp-connector.yaml
@@ -26,7 +26,6 @@ properties:
 
   dp-pwr-supply:
     description: Power supply for the DP_PWR pin
-    maxItems: 1
 
   port:
     $ref: /schemas/graph.yaml#/properties/port
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index 7475e09b068083..d64fc03929be31 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -312,22 +312,25 @@ void __dma_fence_might_wait(void)
 
 
 /**
- * dma_fence_signal_locked - signal completion of a fence
+ * dma_fence_signal_timestamp_locked - signal completion of a fence
  * @fence: the fence to signal
+ * @timestamp: fence signal timestamp in kernel's CLOCK_MONOTONIC time domain
  *
  * Signal completion for software callbacks on a fence, this will unblock
  * dma_fence_wait() calls and run all the callbacks added with
  * dma_fence_add_callback(). Can be called multiple times, but since a fence
  * can only go from the unsignaled to the signaled state and not back, it will
- * only be effective the first time.
+ * only be effective the first time. Set the timestamp provided as the fence
+ * signal timestamp.
  *
- * Unlike dma_fence_signal(), this function must be called with &dma_fence.lock
- * held.
+ * Unlike dma_fence_signal_timestamp(), this function must be called with
+ * &dma_fence.lock held.
  *
  * Returns 0 on success and a negative error value when @fence has been
  * signalled already.
  */
-int dma_fence_signal_locked(struct dma_fence *fence)
+int dma_fence_signal_timestamp_locked(struct dma_fence *fence,
+				      ktime_t timestamp)
 {
 	struct dma_fence_cb *cur, *tmp;
 	struct list_head cb_list;
@@ -341,7 +344,7 @@ int dma_fence_signal_locked(struct dma_fence *fence)
 	/* Stash the cb_list before replacing it with the timestamp */
 	list_replace(&fence->cb_list, &cb_list);
 
-	fence->timestamp = ktime_get();
+	fence->timestamp = timestamp;
 	set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags);
 	trace_dma_fence_signaled(fence);
 
@@ -352,6 +355,59 @@ int dma_fence_signal_locked(struct dma_fence *fence)
 
 	return 0;
 }
+EXPORT_SYMBOL(dma_fence_signal_timestamp_locked);
+
+/**
+ * dma_fence_signal_timestamp - signal completion of a fence
+ * @fence: the fence to signal
+ * @timestamp: fence signal timestamp in kernel's CLOCK_MONOTONIC time domain
+ *
+ * Signal completion for software callbacks on a fence, this will unblock
+ * dma_fence_wait() calls and run all the callbacks added with
+ * dma_fence_add_callback(). Can be called multiple times, but since a fence
+ * can only go from the unsignaled to the signaled state and not back, it will
+ * only be effective the first time. Set the timestamp provided as the fence
+ * signal timestamp.
+ *
+ * Returns 0 on success and a negative error value when @fence has been
+ * signalled already.
+ */
+int dma_fence_signal_timestamp(struct dma_fence *fence, ktime_t timestamp)
+{
+	unsigned long flags;
+	int ret;
+
+	if (!fence)
+		return -EINVAL;
+
+	spin_lock_irqsave(fence->lock, flags);
+	ret = dma_fence_signal_timestamp_locked(fence, timestamp);
+	spin_unlock_irqrestore(fence->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(dma_fence_signal_timestamp);
+
+/**
+ * dma_fence_signal_locked - signal completion of a fence
+ * @fence: the fence to signal
+ *
+ * Signal completion for software callbacks on a fence, this will unblock
+ * dma_fence_wait() calls and run all the callbacks added with
+ * dma_fence_add_callback(). Can be called multiple times, but since a fence
+ * can only go from the unsignaled to the signaled state and not back, it will
+ * only be effective the first time.
+ *
+ * Unlike dma_fence_signal(), this function must be called with &dma_fence.lock
+ * held.
+ *
+ * Returns 0 on success and a negative error value when @fence has been
+ * signalled already.
+ */
+int dma_fence_signal_locked(struct dma_fence *fence)
+{
+	return dma_fence_signal_timestamp_locked(fence, ktime_get());
+}
 EXPORT_SYMBOL(dma_fence_signal_locked);
 
 /**
@@ -379,7 +435,7 @@ int dma_fence_signal(struct dma_fence *fence)
 	tmp = dma_fence_begin_signalling();
 
 	spin_lock_irqsave(fence->lock, flags);
-	ret = dma_fence_signal_locked(fence);
+	ret = dma_fence_signal_timestamp_locked(fence, ktime_get());
 	spin_unlock_irqrestore(fence->lock, flags);
 
 	dma_fence_end_signalling(tmp);
diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c
index afd22c9dbdcfa1..6b5db954569fc4 100644
--- a/drivers/dma-buf/dma-heap.c
+++ b/drivers/dma-buf/dma-heap.c
@@ -52,6 +52,9 @@ static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
 				 unsigned int fd_flags,
 				 unsigned int heap_flags)
 {
+	struct dma_buf *dmabuf;
+	int fd;
+
 	/*
 	 * Allocations from all heaps have to begin
 	 * and end on page boundaries.
@@ -60,7 +63,16 @@ static int dma_heap_buffer_alloc(struct dma_heap *heap, size_t len,
 	if (!len)
 		return -EINVAL;
 
-	return heap->ops->allocate(heap, len, fd_flags, heap_flags);
+	dmabuf = heap->ops->allocate(heap, len, fd_flags, heap_flags);
+	if (IS_ERR(dmabuf))
+		return PTR_ERR(dmabuf);
+
+	fd = dma_buf_fd(dmabuf, fd_flags);
+	if (fd < 0) {
+		dma_buf_put(dmabuf);
+		/* just return, as put will call release and that will free */
+	}
+	return fd;
 }
 
 static int dma_heap_open(struct inode *inode, struct file *file)
diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c
index 364fc2f3e49954..5d64eccd21d638 100644
--- a/drivers/dma-buf/heaps/cma_heap.c
+++ b/drivers/dma-buf/heaps/cma_heap.c
@@ -271,10 +271,10 @@ static const struct dma_buf_ops cma_heap_buf_ops = {
 	.release = cma_heap_dma_buf_release,
 };
 
-static int cma_heap_allocate(struct dma_heap *heap,
-				  unsigned long len,
-				  unsigned long fd_flags,
-				  unsigned long heap_flags)
+static struct dma_buf *cma_heap_allocate(struct dma_heap *heap,
+					 unsigned long len,
+					 unsigned long fd_flags,
+					 unsigned long heap_flags)
 {
 	struct cma_heap *cma_heap = dma_heap_get_drvdata(heap);
 	struct cma_heap_buffer *buffer;
@@ -289,7 +289,7 @@ static int cma_heap_allocate(struct dma_heap *heap,
 
 	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 	if (!buffer)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	INIT_LIST_HEAD(&buffer->attachments);
 	mutex_init(&buffer->lock);
@@ -348,15 +348,7 @@ static int cma_heap_allocate(struct dma_heap *heap,
 		ret = PTR_ERR(dmabuf);
 		goto free_pages;
 	}
-
-	ret = dma_buf_fd(dmabuf, fd_flags);
-	if (ret < 0) {
-		dma_buf_put(dmabuf);
-		/* just return, as put will call release and that will free */
-		return ret;
-	}
-
-	return ret;
+	return dmabuf;
 
 free_pages:
 	kfree(buffer->pages);
@@ -365,7 +357,7 @@ free_cma:
 free_buffer:
 	kfree(buffer);
 
-	return ret;
+	return ERR_PTR(ret);
 }
 
 static const struct dma_heap_ops cma_heap_ops = {
diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
index 17e0e9a68baff4..29e49ac1725135 100644
--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -331,10 +331,10 @@ static struct page *alloc_largest_available(unsigned long size,
 	return NULL;
 }
 
-static int system_heap_allocate(struct dma_heap *heap,
-				unsigned long len,
-				unsigned long fd_flags,
-				unsigned long heap_flags)
+static struct dma_buf *system_heap_allocate(struct dma_heap *heap,
+					    unsigned long len,
+					    unsigned long fd_flags,
+					    unsigned long heap_flags)
 {
 	struct system_heap_buffer *buffer;
 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
@@ -349,7 +349,7 @@ static int system_heap_allocate(struct dma_heap *heap,
 
 	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 	if (!buffer)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	INIT_LIST_HEAD(&buffer->attachments);
 	mutex_init(&buffer->lock);
@@ -363,8 +363,10 @@ static int system_heap_allocate(struct dma_heap *heap,
 		 * Avoid trying to allocate memory if the process
 		 * has been killed by SIGKILL
 		 */
-		if (fatal_signal_pending(current))
+		if (fatal_signal_pending(current)) {
+			ret = -EINTR;
 			goto free_buffer;
+		}
 
 		page = alloc_largest_available(size_remaining, max_order);
 		if (!page)
@@ -397,14 +399,7 @@ static int system_heap_allocate(struct dma_heap *heap,
 		ret = PTR_ERR(dmabuf);
 		goto free_pages;
 	}
-
-	ret = dma_buf_fd(dmabuf, fd_flags);
-	if (ret < 0) {
-		dma_buf_put(dmabuf);
-		/* just return, as put will call release and that will free */
-		return ret;
-	}
-	return ret;
+	return dmabuf;
 
 free_pages:
 	for_each_sgtable_sg(table, sg, i) {
@@ -418,7 +413,7 @@ free_buffer:
 		__free_pages(page, compound_order(page));
 	kfree(buffer);
 
-	return ret;
+	return ERR_PTR(ret);
 }
 
 static const struct dma_heap_ops system_heap_ops = {
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 6b116bfd747c3c..7efbccffc2eaf7 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -775,20 +775,19 @@ void drm_event_cancel_free(struct drm_device *dev,
 EXPORT_SYMBOL(drm_event_cancel_free);
 
 /**
- * drm_send_event_locked - send DRM event to file descriptor
+ * drm_send_event_helper - send DRM event to file descriptor
  * @dev: DRM device
  * @e: DRM event to deliver
+ * @timestamp: timestamp to set for the fence event in kernel's CLOCK_MONOTONIC
+ * time domain
  *
- * This function sends the event @e, initialized with drm_event_reserve_init(),
- * to its associated userspace DRM file. Callers must already hold
- * &drm_device.event_lock, see drm_send_event() for the unlocked version.
- *
- * Note that the core will take care of unlinking and disarming events when the
- * corresponding DRM file is closed. Drivers need not worry about whether the
- * DRM file for this event still exists and can call this function upon
- * completion of the asynchronous work unconditionally.
+ * This helper function sends the event @e, initialized with
+ * drm_event_reserve_init(), to its associated userspace DRM file.
+ * The timestamp variant of dma_fence_signal is used when the caller
+ * sends a valid timestamp.
  */
-void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e)
+void drm_send_event_helper(struct drm_device *dev,
+			   struct drm_pending_event *e, ktime_t timestamp)
 {
 	assert_spin_locked(&dev->event_lock);
 
@@ -799,7 +798,10 @@ void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e)
 	}
 
 	if (e->fence) {
-		dma_fence_signal(e->fence);
+		if (timestamp)
+			dma_fence_signal_timestamp(e->fence, timestamp);
+		else
+			dma_fence_signal(e->fence);
 		dma_fence_put(e->fence);
 	}
 
@@ -814,6 +816,48 @@ void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e)
 	wake_up_interruptible_poll(&e->file_priv->event_wait,
 		EPOLLIN | EPOLLRDNORM);
 }
+
+/**
+ * drm_send_event_timestamp_locked - send DRM event to file descriptor
+ * @dev: DRM device
+ * @e: DRM event to deliver
+ * @timestamp: timestamp to set for the fence event in kernel's CLOCK_MONOTONIC
+ * time domain
+ *
+ * This function sends the event @e, initialized with drm_event_reserve_init(),
+ * to its associated userspace DRM file. Callers must already hold
+ * &drm_device.event_lock.
+ *
+ * Note that the core will take care of unlinking and disarming events when the
+ * corresponding DRM file is closed. Drivers need not worry about whether the
+ * DRM file for this event still exists and can call this function upon
+ * completion of the asynchronous work unconditionally.
+ */
+void drm_send_event_timestamp_locked(struct drm_device *dev,
+				     struct drm_pending_event *e, ktime_t timestamp)
+{
+	drm_send_event_helper(dev, e, timestamp);
+}
+EXPORT_SYMBOL(drm_send_event_timestamp_locked);
+
+/**
+ * drm_send_event_locked - send DRM event to file descriptor
+ * @dev: DRM device
+ * @e: DRM event to deliver
+ *
+ * This function sends the event @e, initialized with drm_event_reserve_init(),
+ * to its associated userspace DRM file. Callers must already hold
+ * &drm_device.event_lock, see drm_send_event() for the unlocked version.
+ *
+ * Note that the core will take care of unlinking and disarming events when the
+ * corresponding DRM file is closed. Drivers need not worry about whether the
+ * DRM file for this event still exists and can call this function upon
+ * completion of the asynchronous work unconditionally.
+ */
+void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e)
+{
+	drm_send_event_helper(dev, e, 0);
+}
 EXPORT_SYMBOL(drm_send_event_locked);
 
 /**
@@ -836,7 +880,7 @@ void drm_send_event(struct drm_device *dev, struct drm_pending_event *e)
 	unsigned long irqflags;
 
 	spin_lock_irqsave(&dev->event_lock, irqflags);
-	drm_send_event_locked(dev, e);
+	drm_send_event_helper(dev, e, 0);
 	spin_unlock_irqrestore(&dev->event_lock, irqflags);
 }
 EXPORT_SYMBOL(drm_send_event);
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 30912d8f82a545..893165eeddf3f4 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -1006,7 +1006,14 @@ static void send_vblank_event(struct drm_device *dev,
 		break;
 	}
 	trace_drm_vblank_event_delivered(e->base.file_priv, e->pipe, seq);
-	drm_send_event_locked(dev, &e->base);
+	/*
+	 * Use the same timestamp for any associated fence signal to avoid
+	 * mismatch in timestamps for vsync & fence events triggered by the
+	 * same HW event. Frameworks like SurfaceFlinger in Android expects the
+	 * retire-fence timestamp to match exactly with HW vsync as it uses it
+	 * for its software vsync modeling.
+	 */
+	drm_send_event_timestamp_locked(dev, &e->base, now);
 }
 
 /**
diff --git a/drivers/gpu/drm/panel/panel-elida-kd35t133.c b/drivers/gpu/drm/panel/panel-elida-kd35t133.c
index bc36aa3c112343..fe5ac3ef90185d 100644
--- a/drivers/gpu/drm/panel/panel-elida-kd35t133.c
+++ b/drivers/gpu/drm/panel/panel-elida-kd35t133.c
@@ -265,7 +265,8 @@ static int kd35t133_probe(struct mipi_dsi_device *dsi)
 	dsi->lanes = 1;
 	dsi->format = MIPI_DSI_FMT_RGB888;
 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
-			  MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_EOT_PACKET;
+			  MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_EOT_PACKET |
+			  MIPI_DSI_CLOCK_NON_CONTINUOUS;
 
 	drm_panel_init(&ctx->panel, &dsi->dev, &kd35t133_funcs,
 		       DRM_MODE_CONNECTOR_DSI);
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.h b/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
index 4a2099cb582e1c..857d97cdc67c66 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
@@ -17,9 +17,20 @@
 
 #define NUM_YUV2YUV_COEFFICIENTS 12
 
+/* AFBC supports a number of configurable modes. Relevant to us is block size
+ * (16x16 or 32x8), storage modifiers (SPARSE, SPLIT), and the YUV-like
+ * colourspace transform (YTR). 16x16 SPARSE mode is always used. SPLIT mode
+ * could be enabled via the hreg_block_split register, but is not currently
+ * handled. The colourspace transform is implicitly always assumed by the
+ * decoder, so consumers must use this transform as well.
+ *
+ * Failure to match modifiers will cause errors displaying AFBC buffers
+ * produced by conformant AFBC producers, including Mesa.
+ */
 #define ROCKCHIP_AFBC_MOD \
 	DRM_FORMAT_MOD_ARM_AFBC( \
 		AFBC_FORMAT_MOD_BLOCK_SIZE_16x16 | AFBC_FORMAT_MOD_SPARSE \
+			| AFBC_FORMAT_MOD_YTR \
 	)
 
 enum vop_data_format {
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index b65f4b12f98669..20a25660b35b8b 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -959,8 +959,10 @@ static int ttm_bo_bounce_temp_buffer(struct ttm_buffer_object *bo,
 		return ret;
 	/* move to the bounce domain */
 	ret = ttm_bo_handle_move_mem(bo, &hop_mem, false, ctx, NULL);
-	if (ret)
+	if (ret) {
+		ttm_resource_free(bo, &hop_mem);
 		return ret;
+	}
 	return 0;
 }
 
@@ -991,18 +993,19 @@ static int ttm_bo_move_buffer(struct ttm_buffer_object *bo,
 	 * stop and the driver will be called to make
 	 * the second hop.
 	 */
-bounce:
 	ret = ttm_bo_mem_space(bo, placement, &mem, ctx);
 	if (ret)
 		return ret;
+bounce:
 	ret = ttm_bo_handle_move_mem(bo, &mem, false, ctx, &hop);
 	if (ret == -EMULTIHOP) {
 		ret = ttm_bo_bounce_temp_buffer(bo, &mem, ctx, &hop);
 		if (ret)
-			return ret;
+			goto out;
 		/* try and move to final place now. */
 		goto bounce;
 	}
+out:
 	if (ret)
 		ttm_resource_free(bo, &mem);
 	return ret;
diff --git a/drivers/video/fbdev/aty/atyfb_base.c b/drivers/video/fbdev/aty/atyfb_base.c
index 83c8e809955a2b..e946903a86c2d8 100644
--- a/drivers/video/fbdev/aty/atyfb_base.c
+++ b/drivers/video/fbdev/aty/atyfb_base.c
@@ -175,6 +175,15 @@ u32 aty_ld_lcd(int index, const struct atyfb_par *par)
 		return aty_ld_le32(LCD_DATA, par);
 	}
 }
+#else /* defined(CONFIG_PMAC_BACKLIGHT) || defined(CONFIG_FB_ATY_BACKLIGHT) \
+	 defined(CONFIG_FB_ATY_GENERIC_LCD) */
+void aty_st_lcd(int index, u32 val, const struct atyfb_par *par)
+{ }
+
+u32 aty_ld_lcd(int index, const struct atyfb_par *par)
+{
+	return 0;
+}
 #endif /* defined(CONFIG_PMAC_BACKLIGHT) || defined (CONFIG_FB_ATY_GENERIC_LCD) */
 
 #ifdef CONFIG_FB_ATY_GENERIC_LCD
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 716990bace1048..b81b3bfb08c8d7 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -399,6 +399,9 @@ void drm_event_cancel_free(struct drm_device *dev,
 			   struct drm_pending_event *p);
 void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e);
 void drm_send_event(struct drm_device *dev, struct drm_pending_event *e);
+void drm_send_event_timestamp_locked(struct drm_device *dev,
+				     struct drm_pending_event *e,
+				     ktime_t timestamp);
 
 struct file *mock_drm_getfile(struct drm_minor *minor, unsigned int flags);
 
diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
index 09e23adb351d5c..9f12efaaa93ae8 100644
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -372,6 +372,9 @@ static inline void __dma_fence_might_wait(void) {}
 
 int dma_fence_signal(struct dma_fence *fence);
 int dma_fence_signal_locked(struct dma_fence *fence);
+int dma_fence_signal_timestamp(struct dma_fence *fence, ktime_t timestamp);
+int dma_fence_signal_timestamp_locked(struct dma_fence *fence,
+				      ktime_t timestamp);
 signed long dma_fence_default_wait(struct dma_fence *fence,
 				   bool intr, signed long timeout);
 int dma_fence_add_callback(struct dma_fence *fence,
diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h
index 454e354d1ffb7e..5bc5c946af58a1 100644
--- a/include/linux/dma-heap.h
+++ b/include/linux/dma-heap.h
@@ -16,15 +16,15 @@ struct dma_heap;
 
 /**
  * struct dma_heap_ops - ops to operate on a given heap
- * @allocate:		allocate dmabuf and return fd
+ * @allocate:		allocate dmabuf and return struct dma_buf ptr
  *
- * allocate returns dmabuf fd  on success, -errno on error.
+ * allocate returns dmabuf on success, ERR_PTR(-errno) on error.
  */
 struct dma_heap_ops {
-	int (*allocate)(struct dma_heap *heap,
-			unsigned long len,
-			unsigned long fd_flags,
-			unsigned long heap_flags);
+	struct dma_buf *(*allocate)(struct dma_heap *heap,
+				    unsigned long len,
+				    unsigned long fd_flags,
+				    unsigned long heap_flags);
 };
 
 /**