On 21/05/18 18:59, Ezequiel Garcia wrote:
> From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
>
> Receive in-fence from userspace and add support for waiting on them
> before queueing the buffer to the driver. Buffers can't be queued to the
> driver before its fences signal. And a buffer can't be queued to the driver
> out of the order they were queued from userspace. That means that even if
> its fence signals it must wait for all other buffers, ahead of it in the queue,
> to signal first.
>
> If the fence for some buffer fails we do not queue it to the driver,
> instead we mark it as error and wait until the previous buffer is done
> to notify userspace of the error. We wait here to deliver the buffers back
> to userspace in order.
>
> v13: - cleanup implementation.
> - remove wrong Kconfig changes.
> - print noisy warning on unexpected enqueue conditioin
> - schedule a vb2_start_streaming work from the fence callback
>
> v12: fixed dvb_vb2.c usage of vb2_core_qbuf.
>
> v11: - minor doc/comments fixes (Hans Verkuil)
> - reviewed the in-fence path at __fill_v4l2_buffer()
>
> v10: - rename fence to in_fence in many places
> - handle fences signalling with error better (Hans Verkuil)
>
> v9: - improve comments and docs (Hans Verkuil)
> - fix unlocking of vb->fence_cb_lock on vb2_core_qbuf (Hans Verkuil)
> - move in-fences code that was in the out-fences patch here (Alex)
>
> v8: - improve comments about fences with errors
>
> v7: - get rid of the fence array stuff for ordering and just use
> get_num_buffers_ready() (Hans)
> - fix issue of queuing the buffer twice (Hans)
> - avoid the dma_fence_wait() in core_qbuf() (Alex)
> - merge preparation commit in
>
> v6: - With fences always keep the order userspace queues the buffers.
> - Protect in_fence manipulation with a lock (Brian Starkey)
> - check if fences have the same context before adding a fence array
> - Fix last_fence ref unbalance in __set_in_fence() (Brian Starkey)
> - Clean up fence if __set_in_fence() fails (Brian Starkey)
> - treat -EINVAL from dma_fence_add_callback() (Brian Starkey)
>
> v5: - use fence_array to keep buffers ordered in vb2 core when
> needed (Brian Starkey)
> - keep backward compat on the reserved2 field (Brian Starkey)
> - protect fence callback removal with lock (Brian Starkey)
>
> v4: - Add a comment about dma_fence_add_callback() not returning a
> error (Hans)
> - Call dma_fence_put(vb->in_fence) if fence signaled (Hans)
> - select SYNC_FILE under config VIDEOBUF2_CORE (Hans)
> - Move dma_fence_is_signaled() check to __enqueue_in_driver() (Hans)
> - Remove list_for_each_entry() in __vb2_core_qbuf() (Hans)
> - Remove if (vb->state != VB2_BUF_STATE_QUEUED) from
> vb2_start_streaming() (Hans)
> - set IN_FENCE flags on __fill_v4l2_buffer (Hans)
> - Queue buffers to the driver as soon as they are ready (Hans)
> - call fill_user_buffer() after queuing the buffer (Hans)
> - add err: label to clean up fence
> - add dma_fence_wait() before calling vb2_start_streaming()
>
> v3: - document fence parameter
> - remove ternary if at vb2_qbuf() return (Mauro)
> - do not change if conditions behaviour (Mauro)
>
> v2: - fix vb2_queue_or_prepare_buf() ret check
> - remove check for VB2_MEMORY_DMABUF only (Javier)
> - check num of ready buffers to start streaming
> - when queueing, start from the first ready buffer
> - handle queue cancel
>
> Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
> Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
> ---
> drivers/media/common/videobuf2/Kconfig | 1 +
> drivers/media/common/videobuf2/videobuf2-core.c | 224 ++++++++++++++++++++----
> drivers/media/common/videobuf2/videobuf2-v4l2.c | 37 +++-
> drivers/media/dvb-core/dvb_vb2.c | 2 +-
> include/media/videobuf2-core.h | 19 +-
> 5 files changed, 242 insertions(+), 41 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/Kconfig b/drivers/media/common/videobuf2/Kconfig
> index 17c32ea58395..27ad9e8a268b 100644
> --- a/drivers/media/common/videobuf2/Kconfig
> +++ b/drivers/media/common/videobuf2/Kconfig
> @@ -1,6 +1,7 @@
> # Used by drivers that need Videobuf2 modules
> config VIDEOBUF2_CORE
> select DMA_SHARED_BUFFER
> + select SYNC_FILE
> tristate
>
> config VIDEOBUF2_V4L2
> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> index a9a0a9d1decb..86b5ebe25263 100644
> --- a/drivers/media/common/videobuf2/videobuf2-core.c
> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
> @@ -27,6 +27,7 @@
> #include <linux/kthread.h>
>
> #include <media/videobuf2-core.h>
> +#include <media/v4l2-ioctl.h>
> #include <media/v4l2-mc.h>
>
> #include <trace/events/vb2.h>
> @@ -189,6 +190,7 @@ module_param(debug, int, 0644);
>
> static void __vb2_queue_cancel(struct vb2_queue *q);
> static void __enqueue_in_driver(struct vb2_buffer *vb);
> +static void __qbuf_work(struct work_struct *work);
>
> static void __vb2_buffer_free(struct kref *kref)
> {
> @@ -373,6 +375,7 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
> vb->index = q->num_buffers + buffer;
> vb->type = q->type;
> vb->memory = memory;
> + INIT_WORK(&vb->qbuf_work, __qbuf_work);
> for (plane = 0; plane < num_planes; ++plane) {
> vb->planes[plane].length = plane_sizes[plane];
> vb->planes[plane].min_length = plane_sizes[plane];
> @@ -932,21 +935,12 @@ void *vb2_plane_cookie(struct vb2_buffer *vb, unsigned int plane_no)
> }
> EXPORT_SYMBOL_GPL(vb2_plane_cookie);
>
> -void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
> +static void vb2_process_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
> {
> struct vb2_queue *q = vb->vb2_queue;
> unsigned long flags;
> unsigned int plane;
>
> - if (WARN_ON(vb->state != VB2_BUF_STATE_ACTIVE))
> - return;
> -
> - if (WARN_ON(state != VB2_BUF_STATE_DONE &&
> - state != VB2_BUF_STATE_ERROR &&
> - state != VB2_BUF_STATE_QUEUED &&
> - state != VB2_BUF_STATE_REQUEUEING))
> - state = VB2_BUF_STATE_ERROR;
> -
> #ifdef CONFIG_VIDEO_ADV_DEBUG
> /*
> * Although this is not a callback, it still does have to balance
> @@ -962,6 +956,9 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
> call_void_memop(vb, finish, vb->planes[plane].mem_priv);
>
> spin_lock_irqsave(&q->done_lock, flags);
> + if (vb->state == VB2_BUF_STATE_ACTIVE)
> + atomic_dec(&q->owned_by_drv_count);
> +
> if (state == VB2_BUF_STATE_QUEUED ||
> state == VB2_BUF_STATE_REQUEUEING) {
> vb->state = VB2_BUF_STATE_QUEUED;
> @@ -970,7 +967,7 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
> list_add_tail(&vb->done_entry, &q->done_list);
> vb->state = state;
> }
> - atomic_dec(&q->owned_by_drv_count);
> +
> spin_unlock_irqrestore(&q->done_lock, flags);
>
> trace_vb2_buf_done(q, vb);
> @@ -987,6 +984,47 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
> wake_up(&q->done_wq);
> break;
> }
> +
> +}
> +
> +void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
> +{
> + struct vb2_buffer *next;
> + struct vb2_queue *q;
> +
> + dprintk(4, "called done on buffer %d state: %d -> %d\n",
> + vb->index, vb->state, state);
> +
> + if (vb->state == VB2_BUF_STATE_ERROR)
> + return;
> + if (WARN_ON(vb->state != VB2_BUF_STATE_ACTIVE))
> + return;
> +
> + if (WARN_ON(state != VB2_BUF_STATE_DONE &&
> + state != VB2_BUF_STATE_ERROR &&
> + state != VB2_BUF_STATE_QUEUED &&
> + state != VB2_BUF_STATE_REQUEUEING))
> + state = VB2_BUF_STATE_ERROR;
> +
> + vb2_process_buffer_done(vb, state);
> +
> + /*
> + * Check if there is any buffer with an in-fence error in the next
> + * position of the queue. Buffers whose in-fence signaled with error
> + * are not queued to the driver and kept on the queue until the buffer
> + * before them is done.
> + * So here we process any existing buffers with in-fence errors and
> + * wake up userspace.
> + */
> + q = vb->vb2_queue;
> + next = list_next_entry(vb, queued_entry);
> + list_for_each_entry_from(next, &q->queued_list, queued_entry) {
> + if (!next->in_fence || !next->in_fence->error)
> + break;
> + if (next->in_fence && next->in_fence->error &&
> + vb->state != VB2_BUF_STATE_ERROR)
> + vb2_process_buffer_done(next, VB2_BUF_STATE_ERROR);
> + }
> }
> EXPORT_SYMBOL_GPL(vb2_buffer_done);
>
> @@ -1271,6 +1309,8 @@ static void __enqueue_in_driver(struct vb2_buffer *vb)
> {
> struct vb2_queue *q = vb->vb2_queue;
>
> + if (WARN_ON(vb->state == VB2_BUF_STATE_ACTIVE))
> + return;
> vb->state = VB2_BUF_STATE_ACTIVE;
> atomic_inc(&q->owned_by_drv_count);
>
> @@ -1322,6 +1362,25 @@ static int __buf_prepare(struct vb2_buffer *vb, const void *pb)
> return 0;
> }
>
> +static int __get_num_ready_buffers(struct vb2_queue *q)
> +{
> + struct vb2_buffer *vb;
> + int ready_count = 0;
> +
> + /*
> + * Count num of buffers ready in front of the queued_list.
> + * We want to stop counting when we find a buffer with an
> + * unsignaled fence.
> + */
> + list_for_each_entry(vb, &q->queued_list, queued_entry) {
> + if (vb->in_fence && dma_fence_get_status(vb->in_fence) == 0)
> + break;
> + ready_count++;
> + }
> +
> + return ready_count;
> +}
> +
> int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb)
> {
> struct vb2_buffer *vb;
> @@ -1338,7 +1397,7 @@ int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb)
> if (ret)
> return ret;
>
> - /* Fill buffer information for the userspace */
> + /* Fill buffer information for userspace */
> call_void_bufop(q, fill_user_buffer, vb, pb);
>
> dprintk(2, "prepare of buffer %d succeeded\n", vb->index);
> @@ -1364,11 +1423,16 @@ static int vb2_start_streaming(struct vb2_queue *q)
> int ret;
>
> /*
> - * If any buffers were queued before streamon,
> - * we can now pass them to driver for processing.
> + * Activate all buffers currently queued,
> + * until we get an unsignaled fence.
> */
> - list_for_each_entry(vb, &q->queued_list, queued_entry)
> + list_for_each_entry(vb, &q->queued_list, queued_entry) {
> + if (vb->state != VB2_BUF_STATE_QUEUED)
I prefer: if (vb->state == VB2_BUF_STATE_ERROR)
It also needs a comment.
> + continue;
> + if (vb->in_fence && dma_fence_get_status(vb->in_fence) == 0)
> + break;
> __enqueue_in_driver(vb);
> + }
>
> /* Tell the driver to start streaming */
> q->start_streaming_called = 1;
> @@ -1410,7 +1474,41 @@ static int vb2_start_streaming(struct vb2_queue *q)
> return ret;
> }
>
> -int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb)
> +static void __qbuf_work(struct work_struct *work)
> +{
> + struct vb2_buffer *vb;
> + struct vb2_queue *q;
> +
> + vb = container_of(work, struct vb2_buffer, qbuf_work);
> + q = vb->vb2_queue;
> +
> + if (q->lock)
> + mutex_lock(q->lock);
> + /* By the time we run, the buffer state could have changed,
> + * so we need to check it's in the queued state.
> + * This is the only valid state.
> + */
> + if (q->start_streaming_called && vb->state == VB2_BUF_STATE_QUEUED)
> + __enqueue_in_driver(vb);
> +
> + if (q->streaming && !q->start_streaming_called &&
> + __get_num_ready_buffers(q) >= q->min_buffers_needed)
> + vb2_start_streaming(q);
What happens if vb2_start_streaming fails?
> +
> + if (q->lock)
> + mutex_unlock(q->lock);
> + __vb2_buffer_put(vb);
> +}
> +
> +static void vb2_qbuf_fence_cb(struct dma_fence *f, struct dma_fence_cb *cb)
> +{
> + struct vb2_buffer *vb = container_of(cb, struct vb2_buffer, fence_cb);
> +
> + schedule_work(&vb->qbuf_work);
> +}
> +
> +int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
> + struct dma_fence *in_fence)
> {
> struct vb2_buffer *vb;
> int ret;
> @@ -1421,16 +1519,18 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb)
> case VB2_BUF_STATE_DEQUEUED:
> ret = __buf_prepare(vb, pb);
> if (ret)
> - return ret;
> + goto err_release;
> break;
> case VB2_BUF_STATE_PREPARED:
> break;
> case VB2_BUF_STATE_PREPARING:
> dprintk(1, "buffer still being prepared\n");
> - return -EINVAL;
> + ret = -EINVAL;
> + goto err_release;
> default:
> dprintk(1, "invalid buffer state %d\n", vb->state);
> - return -EINVAL;
> + ret = -EINVAL;
> + goto err_release;
> }
>
> /*
> @@ -1448,15 +1548,44 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb)
> trace_vb2_qbuf(q, vb);
>
> /*
> - * If already streaming, give the buffer to driver for processing.
> - * If not, the buffer will be given to driver on next streamon.
> + * If the fence didn't signal yet, we setup a callback to queue
> + * the buffer once the fence signals. If the fence already signaled,
> + * then we lose the reference and queue the buffer.
> */
> - if (q->start_streaming_called)
> - __enqueue_in_driver(vb);
> + if (in_fence) {
> + WARN_ON(vb->in_fence);
> + vb->in_fence = in_fence;
> + __vb2_buffer_get(vb);
> + ret = dma_fence_add_callback(in_fence, &vb->fence_cb,
> + vb2_qbuf_fence_cb);
> + /* is the fence signaled? */
> + if (ret == -ENOENT) {
> + if (in_fence->error)
> + /* error-signaled fence, reject this buffer */
> + goto err_release;
> + dma_fence_put(in_fence);
> + vb->in_fence = NULL;
> + __vb2_buffer_put(vb);
> + } else if (ret) {
> + goto err_release;
> + }
> + }
>
> - /* Fill buffer information for the userspace */
> - if (pb)
> - call_void_bufop(q, fill_user_buffer, vb, pb);
> + /*
> + * If already streaming and there is no fence to wait on
> + * give the buffer to driver for processing.
> + */
> + if (q->start_streaming_called) {
> + struct vb2_buffer *b;
> +
> + list_for_each_entry(b, &q->queued_list, queued_entry) {
> + if (b->state != VB2_BUF_STATE_QUEUED)
b->state == VB2_BUF_STATE_ERROR
> + continue;
> + if (b->in_fence && dma_fence_get_status(b->in_fence) == 0)
> + break;
> + __enqueue_in_driver(b);
> + }
> + }
>
> /*
> * If streamon has been called, and we haven't yet called
> @@ -1465,14 +1594,32 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb)
> * then we can finally call start_streaming().
> */
> if (q->streaming && !q->start_streaming_called &&
> - q->queued_count >= q->min_buffers_needed) {
> + __get_num_ready_buffers(q) >= q->min_buffers_needed) {
> ret = vb2_start_streaming(q);
> if (ret)
> - return ret;
> + goto err_release;
> }
>
> + /* Fill buffer information for userspace */
> + if (pb)
> + call_void_bufop(q, fill_user_buffer, vb, pb);
> +
> dprintk(2, "qbuf of buffer %d succeeded\n", vb->index);
> return 0;
> +
> +err_release:
> + /* Fill buffer information for userspace */
> + if (pb)
> + call_void_bufop(q, fill_user_buffer, vb, pb);
> +
> + if (in_fence) {
> + dma_fence_put(in_fence);
> + vb->in_fence = NULL;
> + __vb2_buffer_put(vb);
> + }
> +
> + return ret;
> +
> }
> EXPORT_SYMBOL_GPL(vb2_core_qbuf);
>
> @@ -1615,7 +1762,12 @@ static void __vb2_dqbuf(struct vb2_buffer *vb)
> return;
>
> vb->state = VB2_BUF_STATE_DEQUEUED;
> -
> + if (vb->in_fence) {
> + if (dma_fence_remove_callback(vb->in_fence, &vb->fence_cb))
> + __vb2_buffer_put(vb);
> + dma_fence_put(vb->in_fence);
> + vb->in_fence = NULL;
> + }
> /* unmap DMABUF buffer */
> if (q->memory == VB2_MEMORY_DMABUF)
> for (i = 0; i < vb->num_planes; ++i) {
> @@ -1653,7 +1805,7 @@ int vb2_core_dqbuf(struct vb2_queue *q, unsigned int *pindex, void *pb,
> if (pindex)
> *pindex = vb->index;
>
> - /* Fill buffer information for the userspace */
> + /* Fill buffer information for userspace */
> if (pb)
> call_void_bufop(q, fill_user_buffer, vb, pb);
>
> @@ -1700,8 +1852,8 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
> if (WARN_ON(atomic_read(&q->owned_by_drv_count))) {
> for (i = 0; i < q->num_buffers; ++i)
> if (q->bufs[i]->state == VB2_BUF_STATE_ACTIVE) {
> - pr_warn("driver bug: stop_streaming operation is leaving buf %p in active state\n",
> - q->bufs[i]);
> + pr_warn("driver bug: stop_streaming operation is leaving buf[%d] 0x%p in active state\n",
> + q->bufs[i]->index, q->bufs[i]);
> vb2_buffer_done(q->bufs[i], VB2_BUF_STATE_ERROR);
> }
Shouldn't any pending fences be canceled here?
I feel uncomfortable with the refcounting of buffers, I'd rather that when we
cancel the queue all fences for buffers are removed/canceled/whatever.
Is there any reason for refcounting if we cancel all pending fences here?
Note that besides canceling fences you also need to cancel/flush __qbuf_work.
> /* Must be zero now */
> @@ -1783,7 +1935,7 @@ int vb2_core_streamon(struct vb2_queue *q, unsigned int type)
> * Tell driver to start streaming provided sufficient buffers
> * are available.
> */
> - if (q->queued_count >= q->min_buffers_needed) {
> + if (__get_num_ready_buffers(q) >= q->min_buffers_needed) {
> ret = v4l_vb2q_enable_media_source(q);
> if (ret)
> return ret;
> @@ -2305,7 +2457,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read)
> * Queue all buffers.
> */
> for (i = 0; i < q->num_buffers; i++) {
> - ret = vb2_core_qbuf(q, i, NULL);
> + ret = vb2_core_qbuf(q, i, NULL, NULL);
> if (ret)
> goto err_reqbufs;
> fileio->bufs[i].queued = 1;
> @@ -2484,7 +2636,7 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_
>
> if (copy_timestamp)
> b->timestamp = ktime_get_ns();
> - ret = vb2_core_qbuf(q, index, NULL);
> + ret = vb2_core_qbuf(q, index, NULL, NULL);
> dprintk(5, "vb2_dbuf result: %d\n", ret);
> if (ret)
> return ret;
> @@ -2587,7 +2739,7 @@ static int vb2_thread(void *data)
> if (copy_timestamp)
> vb->timestamp = ktime_get_ns();
> if (!threadio->stop)
> - ret = vb2_core_qbuf(q, vb->index, NULL);
> + ret = vb2_core_qbuf(q, vb->index, NULL, NULL);
> call_void_qop(q, wait_prepare, q);
> if (ret || threadio->stop)
> break;
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> index 8312f61adfa6..ac14cc8ab1c5 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -23,6 +23,7 @@
> #include <linux/sched.h>
> #include <linux/freezer.h>
> #include <linux/kthread.h>
> +#include <linux/sync_file.h>
>
> #include <media/v4l2-dev.h>
> #include <media/v4l2-fh.h>
> @@ -178,6 +179,22 @@ static int vb2_queue_or_prepare_buf(struct vb2_queue *q, struct v4l2_buffer *b,
> return -EINVAL;
> }
>
> + if ((b->fence_fd != 0 && b->fence_fd != -1) &&
> + !(b->flags & V4L2_BUF_FLAG_IN_FENCE)) {
> + dprintk(1, "%s: fence_fd set without IN_FENCE flag\n", opname);
> + return -EINVAL;
I'm not sure we need this. If V4L2_BUF_FLAG_IN_FENCE is not set, then fence_fd
can just be ignored (and it is set to -1 anyway when the ioctl returns).
> + }
> +
> + if (b->fence_fd < 0 && (b->flags & V4L2_BUF_FLAG_IN_FENCE)) {
> + dprintk(1, "%s: IN_FENCE flag set but no fence_fd\n", opname);
> + return -EINVAL;
> + }
> +
> + if ((b->flags & V4L2_BUF_FLAG_IN_FENCE) && !q->lock) {
> + pr_warn("%s: IN_FENCE flag set, but no queue lock\n", opname);
> + b->flags &= ~V4L2_BUF_FLAG_IN_FENCE;
> + }
> +
> return __verify_planes_array(q->bufs[b->index], b);
> }
>
> @@ -210,6 +227,11 @@ static void __fill_v4l2_buffer(struct vb2_buffer *vb, void *pb)
> else
> b->fence_fd = 0;
>
> + if (vb->in_fence)
> + b->flags |= V4L2_BUF_FLAG_IN_FENCE;
> + else
> + b->flags &= ~V4L2_BUF_FLAG_IN_FENCE;
> +
> if (q->is_multiplanar) {
> /*
> * Fill in plane-related data if userspace provided an array
> @@ -566,6 +588,7 @@ EXPORT_SYMBOL_GPL(vb2_create_bufs);
>
> int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
> {
> + struct dma_fence *in_fence = NULL;
> int ret;
>
> if (vb2_fileio_is_active(q)) {
> @@ -574,7 +597,19 @@ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
> }
>
> ret = vb2_queue_or_prepare_buf(q, b, "qbuf");
> - return ret ? ret : vb2_core_qbuf(q, b->index, b);
> + if (ret)
> + return ret;
> +
> + if (b->flags & V4L2_BUF_FLAG_IN_FENCE) {
> + in_fence = sync_file_get_fence(b->fence_fd);
> + if (!in_fence) {
> + dprintk(1, "failed to get in-fence from fd %d\n",
> + b->fence_fd);
> + return -EINVAL;
> + }
> + }
> +
> + return vb2_core_qbuf(q, b->index, b, in_fence);
> }
> EXPORT_SYMBOL_GPL(vb2_qbuf);
>
> diff --git a/drivers/media/dvb-core/dvb_vb2.c b/drivers/media/dvb-core/dvb_vb2.c
> index b811adf88afa..7da53f10db1a 100644
> --- a/drivers/media/dvb-core/dvb_vb2.c
> +++ b/drivers/media/dvb-core/dvb_vb2.c
> @@ -385,7 +385,7 @@ int dvb_vb2_qbuf(struct dvb_vb2_ctx *ctx, struct dmx_buffer *b)
> {
> int ret;
>
> - ret = vb2_core_qbuf(&ctx->vb_q, b->index, b);
> + ret = vb2_core_qbuf(&ctx->vb_q, b->index, b, NULL);
> if (ret) {
> dprintk(1, "[%s] index=%d errno=%d\n", ctx->name,
> b->index, ret);
> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> index 71538ae2c255..ddd555f59dbf 100644
> --- a/include/media/videobuf2-core.h
> +++ b/include/media/videobuf2-core.h
> @@ -14,6 +14,7 @@
>
> #include <linux/bitops.h>
> #include <linux/dma-buf.h>
> +#include <linux/dma-fence.h>
> #include <linux/kref.h>
> #include <linux/mm_types.h>
> #include <linux/mutex.h>
> @@ -257,6 +258,10 @@ struct vb2_buffer {
> * done_entry: entry on the list that stores all buffers ready
> * to be dequeued to userspace
> * vb2_plane: per-plane information; do not change
> + * in_fence: fence received from vb2 client to wait on before
> + * using the buffer (queueing to the driver)
> + * fence_cb: fence callback information
> + * qbuf_work: work for deferred qbuf operation
> */
> struct kref refcount;
> enum vb2_buffer_state state;
> @@ -264,6 +269,11 @@ struct vb2_buffer {
> struct vb2_plane planes[VB2_MAX_PLANES];
> struct list_head queued_entry;
> struct list_head done_entry;
> +
> + struct dma_fence *in_fence;
> + struct dma_fence_cb fence_cb;
> + struct work_struct qbuf_work;
> +
> #ifdef CONFIG_VIDEO_ADV_DEBUG
> /*
> * Counters for how often these buffer-related ops are
> @@ -488,8 +498,9 @@ struct vb2_buf_ops {
> * @lock: pointer to a mutex that protects the &struct vb2_queue. The
> * driver can set this to a mutex to let the v4l2 core serialize
> * the queuing ioctls. If the driver wants to handle locking
> - * itself, then this should be set to NULL. This lock is not used
> - * by the videobuf2 core API.
> + * itself, then this should be set to NULL. This lock is required
> + * by the videobuf2 core only on the fence-deferred start streaming
> + * path.
> * @owner: The filehandle that 'owns' the buffers, i.e. the filehandle
> * that called reqbufs, create_buffers or started fileio.
> * This field is not used by the videobuf2 core API, but it allows
> @@ -789,6 +800,7 @@ int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
> * @index: id number of the buffer
> * @pb: buffer structure passed from userspace to
> * v4l2_ioctl_ops->vidioc_qbuf handler in driver
> + * @in_fence: in-fence to wait on before queueing the buffer
> *
> * Videobuf2 core helper to implement VIDIOC_QBUF() operation. It is called
> * internally by VB2 by an API-specific handler, like ``videobuf2-v4l2.h``.
> @@ -803,7 +815,8 @@ int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb);
> *
> * Return: returns zero on success; an error code otherwise.
> */
> -int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb);
> +int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
> + struct dma_fence *in_fence);
>
> /**
> * vb2_core_dqbuf() - Dequeue a buffer to the userspace
>
Regards,
Hans
