On 2018å¹´08æ??23æ?¥ 17:08, Daniel Vetter wrote:
> On Thu, Aug 23, 2018 at 04:25:42PM +0800, Chunming Zhou wrote:
>> VK_KHR_timeline_semaphore:
>> This extension introduces a new type of semaphore that has an integer payload
>> identifying a point in a timeline. Such timeline semaphores support the
>> following operations:
>> * Host query - A host operation that allows querying the payload of the
>> timeline semaphore.
>> * Host wait - A host operation that allows a blocking wait for a
>> timeline semaphore to reach a specified value.
>> * Device wait - A device operation that allows waiting for a
>> timeline semaphore to reach a specified value.
>> * Device signal - A device operation that allows advancing the
>> timeline semaphore to a specified value.
>>
>> Since it's a timeline, that means the front time point(PT) always is signaled before the late PT.
>> a. signal PT design:
>> Signal PT fence N depends on PT[N-1] fence and signal opertion fence, when PT[N] fence is signaled,
>> the timeline will increase to value of PT[N].
>> b. wait PT design:
>> Wait PT fence is signaled by reaching timeline point value, when timeline is increasing, will compare
>> wait PTs value with new timeline value, if PT value is lower than timeline value, then wait PT will be
>> signaled, otherwise keep in list. semaphore wait operation can wait on any point of timeline,
>> so need a RB tree to order them. And wait PT could ahead of signal PT, we need a sumission fence to
>> perform that.
>>
>> v2:
>> 1. remove unused DRM_SYNCOBJ_CREATE_TYPE_NORMAL. (Christian)
>> 2. move unexposed denitions to .c file. (Daniel Vetter)
>> 3. split up the change to drm_syncobj_find_fence() in a separate patch. (Christian)
>> 4. split up the change to drm_syncobj_replace_fence() in a separate patch.
>> 5. drop the submission_fence implementation and instead use wait_event() for that. (Christian)
>> 6. WARN_ON(point != 0) for NORMAL type syncobj case. (Daniel Vetter)
> Depending upon how it's going to be used, this is the wrong thing to do.
>
>> TODO:
>> 1. CPU query and wait on timeline semaphore.
>> 2. test application (Daniel Vetter)
> I also had some more suggestions, around aligning the two concepts of
> future fences
submission fence is replaced by wait_event, so I don't address your
future fence suggestion. And welcome to explain future fence status.
> and at least trying to merge the timeline and the other
> fence (which really is just a special case of a timeline with only 1
> slot).
Could you detail that? Do you mean merge syncobj->fence to timeline point?
Thanks,
David Zhou
> -Daniel
>
>> Signed-off-by: Chunming Zhou <david1.zhou at amd.com>
>> Cc: Christian Konig <christian.koenig at amd.com>
>> Cc: Dave Airlie <airlied at redhat.com>
>> Cc: Daniel Rakos <Daniel.Rakos at amd.com>
>> Cc: Daniel Vetter <daniel at ffwll.ch>
>> ---
>> drivers/gpu/drm/drm_syncobj.c | 383 +++++++++++++++++++++++++++++++++++++++---
>> include/drm/drm_syncobj.h | 28 +++
>> include/uapi/drm/drm.h | 1 +
>> 3 files changed, 389 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
>> index 6227df2cc0a4..f738d78edf65 100644
>> --- a/drivers/gpu/drm/drm_syncobj.c
>> +++ b/drivers/gpu/drm/drm_syncobj.c
>> @@ -56,6 +56,44 @@
>> #include "drm_internal.h"
>> #include <drm/drm_syncobj.h>
>>
>> +struct drm_syncobj_stub_fence {
>> + struct dma_fence base;
>> + spinlock_t lock;
>> +};
>> +
>> +static const char *drm_syncobj_stub_fence_get_name(struct dma_fence *fence)
>> +{
>> + return "syncobjstub";
>> +}
>> +
>> +static bool drm_syncobj_stub_fence_enable_signaling(struct dma_fence *fence)
>> +{
>> + return !dma_fence_is_signaled(fence);
>> +}
>> +
>> +static const struct dma_fence_ops drm_syncobj_stub_fence_ops = {
>> + .get_driver_name = drm_syncobj_stub_fence_get_name,
>> + .get_timeline_name = drm_syncobj_stub_fence_get_name,
>> + .enable_signaling = drm_syncobj_stub_fence_enable_signaling,
>> + .release = NULL,
>> +};
>> +
>> +struct drm_syncobj_wait_pt {
>> + struct drm_syncobj_stub_fence base;
>> + u64 value;
>> + struct rb_node node;
>> +};
>> +struct drm_syncobj_signal_pt {
>> + struct drm_syncobj_stub_fence base;
>> + struct dma_fence *signal_fence;
>> + struct dma_fence *pre_pt_base;
>> + struct dma_fence_cb signal_cb;
>> + struct dma_fence_cb pre_pt_cb;
>> + struct drm_syncobj *syncobj;
>> + u64 value;
>> + struct list_head list;
>> +};
>> +
>> /**
>> * drm_syncobj_find - lookup and reference a sync object.
>> * @file_private: drm file private pointer
>> @@ -137,6 +175,150 @@ void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,
>> spin_unlock(&syncobj->lock);
>> }
>>
>> +static void drm_syncobj_timeline_signal_wait_pts(struct drm_syncobj *syncobj)
>> +{
>> + struct rb_node *node = NULL;
>> + struct drm_syncobj_wait_pt *wait_pt = NULL;
>> +
>> + spin_lock(&syncobj->lock);
>> + for(node = rb_first(&syncobj->syncobj_timeline.wait_pt_tree);
>> + node != NULL; ) {
>> + wait_pt = rb_entry(node, struct drm_syncobj_wait_pt, node);
>> + node = rb_next(node);
>> + if (wait_pt->value <= syncobj->syncobj_timeline.timeline) {
>> + dma_fence_signal(&wait_pt->base.base);
>> + rb_erase(&wait_pt->node,
>> + &syncobj->syncobj_timeline.wait_pt_tree);
>> + RB_CLEAR_NODE(&wait_pt->node);
>> + /* kfree(wait_pt) is excuted by fence put */
>> + dma_fence_put(&wait_pt->base.base);
>> + } else {
>> + /* the loop is from left to right, the later entry value is
>> + * bigger, so don't need to check any more */
>> + break;
>> + }
>> + }
>> + spin_unlock(&syncobj->lock);
>> +}
>> +
>> +
>> +static void pt_fence_cb(struct drm_syncobj_signal_pt *signal_pt)
>> +{
>> + struct dma_fence *fence = NULL;
>> + struct drm_syncobj *syncobj;
>> +
>> + fence = signal_pt->signal_fence;
>> + signal_pt->signal_fence = NULL;
>> + dma_fence_put(fence);
>> + fence = signal_pt->pre_pt_base;
>> + signal_pt->pre_pt_base = NULL;
>> + dma_fence_put(fence);
>> +
>> + syncobj = signal_pt->syncobj;
>> + spin_lock(&syncobj->lock);
>> + list_del(&signal_pt->list);
>> + syncobj->syncobj_timeline.timeline = signal_pt->value;
>> + spin_unlock(&syncobj->lock);
>> + /* kfree(signal_pt) will be executed by below fence put */
>> + dma_fence_put(&signal_pt->base.base);
>> + drm_syncobj_timeline_signal_wait_pts(syncobj);
>> +}
>> +static void pt_signal_fence_func(struct dma_fence *fence,
>> + struct dma_fence_cb *cb)
>> +{
>> + struct drm_syncobj_signal_pt *signal_pt =
>> + container_of(cb, struct drm_syncobj_signal_pt, signal_cb);
>> +
>> + if (signal_pt->pre_pt_base &&
>> + !dma_fence_is_signaled(signal_pt->pre_pt_base))
>> + return;
>> +
>> + pt_fence_cb(signal_pt);
>> +}
>> +static void pt_pre_fence_func(struct dma_fence *fence,
>> + struct dma_fence_cb *cb)
>> +{
>> + struct drm_syncobj_signal_pt *signal_pt =
>> + container_of(cb, struct drm_syncobj_signal_pt, pre_pt_cb);
>> +
>> + if (signal_pt->signal_fence &&
>> + !dma_fence_is_signaled(signal_pt->pre_pt_base))
>> + return;
>> +
>> + pt_fence_cb(signal_pt);
>> +}
>> +
>> +static int drm_syncobj_timeline_replace_fence(struct drm_syncobj *syncobj,
>> + struct dma_fence *fence,
>> + u64 point)
>> +{
>> + struct drm_syncobj_signal_pt *signal_pt =
>> + kzalloc(sizeof(struct drm_syncobj_signal_pt), GFP_KERNEL);
>> + struct drm_syncobj_signal_pt *tail_pt;
>> + struct dma_fence *tail_pt_fence = NULL;
>> + int ret = 0;
>> +
>> + if (!signal_pt)
>> + return -ENOMEM;
>> + if (syncobj->syncobj_timeline.signal_point >= point) {
>> + DRM_WARN("A later signal is ready!");
>> + goto out;
>> + }
>> + if (fence)
>> + dma_fence_get(fence);
>> + spin_lock(&syncobj->lock);
>> + spin_lock_init(&signal_pt->base.lock);
>> + dma_fence_init(&signal_pt->base.base,
>> + &drm_syncobj_stub_fence_ops,
>> + &signal_pt->base.lock,
>> + syncobj->syncobj_timeline.timeline_context, point);
>> + signal_pt->signal_fence =
>> + rcu_dereference_protected(fence,
>> + lockdep_is_held(&fence->lock));
>> + if (!list_empty(&syncobj->syncobj_timeline.signal_pt_list)) {
>> + tail_pt = list_last_entry(&syncobj->syncobj_timeline.signal_pt_list,
>> + struct drm_syncobj_signal_pt, list);
>> + tail_pt_fence = &tail_pt->base.base;
>> + if (dma_fence_is_signaled(tail_pt_fence))
>> + tail_pt_fence = NULL;
>> + }
>> + if (tail_pt_fence)
>> + signal_pt->pre_pt_base =
>> + dma_fence_get(rcu_dereference_protected(tail_pt_fence,
>> + lockdep_is_held(&tail_pt_fence->lock)));
>> +
>> + signal_pt->value = point;
>> + syncobj->syncobj_timeline.signal_point = point;
>> + signal_pt->syncobj = syncobj;
>> + INIT_LIST_HEAD(&signal_pt->list);
>> + list_add_tail(&signal_pt->list, &syncobj->syncobj_timeline.signal_pt_list);
>> + spin_unlock(&syncobj->lock);
>> + wake_up_all(&syncobj->syncobj_timeline.wq);
>> + /**
>> + * Every pt is depending on signal fence and previous pt fence, add
>> + * callbacks to them
>> + */
>> + if (!dma_fence_is_signaled(signal_pt->signal_fence))
>> + dma_fence_add_callback(signal_pt->signal_fence,
>> + &signal_pt->signal_cb,
>> + pt_signal_fence_func);
>> + else
>> + pt_signal_fence_func(signal_pt->signal_fence,
>> + &signal_pt->signal_cb);
>> + if (signal_pt->pre_pt_base && !dma_fence_is_signaled(signal_pt->pre_pt_base))
>> + dma_fence_add_callback(signal_pt->pre_pt_base,
>> + &signal_pt->pre_pt_cb,
>> + pt_pre_fence_func);
>> + else
>> + pt_pre_fence_func(signal_pt->pre_pt_base, &signal_pt->pre_pt_cb);
>> +
>> +
>> + return 0;
>> +out:
>> + kfree(signal_pt);
>> + return ret;
>> +}
>> +
>> /**
>> * drm_syncobj_replace_fence - replace fence in a sync object.
>> * @syncobj: Sync object to replace fence in
>> @@ -152,6 +334,11 @@ void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
>> struct dma_fence *old_fence;
>> struct drm_syncobj_cb *cur, *tmp;
>>
>> + if (syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) {
>> + drm_syncobj_timeline_replace_fence(syncobj, fence,
>> + point);
>> + return;
>> + }
>> if (fence)
>> dma_fence_get(fence);
>>
>> @@ -174,28 +361,6 @@ void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
>> }
>> EXPORT_SYMBOL(drm_syncobj_replace_fence);
>>
>> -struct drm_syncobj_stub_fence {
>> - struct dma_fence base;
>> - spinlock_t lock;
>> -};
>> -
>> -static const char *drm_syncobj_stub_fence_get_name(struct dma_fence *fence)
>> -{
>> - return "syncobjstub";
>> -}
>> -
>> -static bool drm_syncobj_stub_fence_enable_signaling(struct dma_fence *fence)
>> -{
>> - return !dma_fence_is_signaled(fence);
>> -}
>> -
>> -static const struct dma_fence_ops drm_syncobj_stub_fence_ops = {
>> - .get_driver_name = drm_syncobj_stub_fence_get_name,
>> - .get_timeline_name = drm_syncobj_stub_fence_get_name,
>> - .enable_signaling = drm_syncobj_stub_fence_enable_signaling,
>> - .release = NULL,
>> -};
>> -
>> static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
>> {
>> struct drm_syncobj_stub_fence *fence;
>> @@ -215,6 +380,121 @@ static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
>> return 0;
>> }
>>
>> +static struct drm_syncobj_wait_pt *
>> +drm_syncobj_timeline_lookup_wait_pt(struct drm_syncobj *syncobj, u64 point)
>> +{
>> + struct rb_node *node = syncobj->syncobj_timeline.wait_pt_tree.rb_node;
>> + struct drm_syncobj_wait_pt *wait_pt = NULL;
>> +
>> +
>> + spin_lock(&syncobj->lock);
>> + while(node) {
>> + int result = point - wait_pt->value;
>> +
>> + wait_pt = rb_entry(node, struct drm_syncobj_wait_pt, node);
>> + if (result < 0)
>> + node = node->rb_left;
>> + else if (result > 0)
>> + node = node->rb_right;
>> + else
>> + break;
>> + }
>> + spin_unlock(&syncobj->lock);
>> +
>> + return wait_pt;
>> +}
>> +
>> +static struct drm_syncobj_wait_pt *
>> +drm_syncobj_timeline_create_wait_pt(struct drm_syncobj *syncobj, u64 point)
>> +{
>> + struct drm_syncobj_wait_pt *wait_pt;
>> + struct rb_node **new = &(syncobj->syncobj_timeline.wait_pt_tree.rb_node), *parent = NULL;
>> +
>> + wait_pt = kzalloc(sizeof(*wait_pt), GFP_KERNEL);
>> + if (!wait_pt)
>> + return NULL;
>> + spin_lock_init(&wait_pt->base.lock);
>> + dma_fence_init(&wait_pt->base.base,
>> + &drm_syncobj_stub_fence_ops,
>> + &wait_pt->base.lock,
>> + syncobj->syncobj_timeline.timeline_context, point);
>> + wait_pt->value = point;
>> +
>> + /* wait pt must be in an order, so that we can easily lookup and signal
>> + * it */
>> + spin_lock(&syncobj->lock);
>> + if (point <= syncobj->syncobj_timeline.timeline)
>> + dma_fence_signal(&wait_pt->base.base);
>> + while(*new) {
>> + struct drm_syncobj_wait_pt *this =
>> + rb_entry(*new, struct drm_syncobj_wait_pt, node);
>> + int result = wait_pt->value - this->value;
>> +
>> + parent = *new;
>> + if (result < 0)
>> + new = &((*new)->rb_left);
>> + else if (result > 0)
>> + new = &((*new)->rb_right);
>> + else
>> + goto exist;
>> + }
>> +
>> + rb_link_node(&wait_pt->node, parent, new);
>> + rb_insert_color(&wait_pt->node, &syncobj->syncobj_timeline.wait_pt_tree);
>> + spin_unlock(&syncobj->lock);
>> + return wait_pt;
>> +exist:
>> + spin_unlock(&syncobj->lock);
>> + dma_fence_put(&wait_pt->base.base);
>> + wait_pt = drm_syncobj_timeline_lookup_wait_pt(syncobj, point);
>> + return wait_pt;
>> +}
>> +
>> +static struct dma_fence *
>> +drm_syncobj_timeline_point_get(struct drm_syncobj *syncobj, u64 point, u64 flag)
>> +{
>> + struct drm_syncobj_wait_pt *wait_pt;
>> +
>> + /* already signaled, simply return a signaled stub fence */
>> + if (point <= syncobj->syncobj_timeline.timeline) {
>> + struct drm_syncobj_stub_fence *fence;
>> +
>> + fence = kzalloc(sizeof(*fence), GFP_KERNEL);
>> + if (fence == NULL)
>> + return NULL;
>> +
>> + spin_lock_init(&fence->lock);
>> + dma_fence_init(&fence->base, &drm_syncobj_stub_fence_ops,
>> + &fence->lock, 0, 0);
>> + dma_fence_signal(&fence->base);
>> + return &fence->base;
>> + }
>> +
>> + /* check if the wait pt exists */
>> + wait_pt = drm_syncobj_timeline_lookup_wait_pt(syncobj, point);
>> + if (!wait_pt) {
>> + /* This is a new wait pt, so create it */
>> + wait_pt = drm_syncobj_timeline_create_wait_pt(syncobj, point);
>> + if (!wait_pt)
>> + return NULL;
>> + }
>> + if (wait_pt) {
>> + struct dma_fence *fence;
>> + int ret =
>> + wait_event_interruptible_timeout(syncobj->syncobj_timeline.wq,
>> + wait_pt->value <= syncobj->syncobj_timeline.signal_point,
>> + msecs_to_jiffies(10000)); /* wait 10s */
>> +
>> + if (ret <= 0)
>> + return NULL;
>> + rcu_read_lock();
>> + fence = dma_fence_get_rcu(&wait_pt->base.base);
>> + rcu_read_unlock();
>> + return fence;
>> + }
>> + return NULL;
>> +}
>> +
>> /**
>> * drm_syncobj_find_fence - lookup and reference the fence in a sync object
>> * @file_private: drm file private pointer
>> @@ -240,7 +520,17 @@ int drm_syncobj_find_fence(struct drm_file *file_private,
>> if (!syncobj)
>> return -ENOENT;
>>
>> - *fence = drm_syncobj_fence_get(syncobj);
>> + if (syncobj->type == DRM_SYNCOBJ_TYPE_NORMAL) {
>> + /* NORMAL syncobj doesn't care point value */
>> + WARN_ON(point != 0);
>> + *fence = drm_syncobj_fence_get(syncobj);
>> + } else if (syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) {
>> + *fence = drm_syncobj_timeline_point_get(syncobj, point,
>> + DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT);
>> + } else {
>> + DRM_ERROR("Don't support this type syncobj\n");
>> + *fence = NULL;
>> + }
>> if (!*fence) {
>> ret = -EINVAL;
>> }
>> @@ -249,6 +539,34 @@ int drm_syncobj_find_fence(struct drm_file *file_private,
>> }
>> EXPORT_SYMBOL(drm_syncobj_find_fence);
>>
>> +static void drm_syncobj_timeline_fini(struct drm_syncobj *syncobj,
>> + struct drm_syncobj_timeline *syncobj_timeline)
>> +{
>> + struct rb_node *node = NULL;
>> + struct drm_syncobj_wait_pt *wait_pt = NULL;
>> + struct drm_syncobj_signal_pt *signal_pt = NULL, *tmp;
>> +
>> + spin_lock(&syncobj->lock);
>> + for(node = rb_first(&syncobj_timeline->wait_pt_tree);
>> + node != NULL; ) {
>> + wait_pt = rb_entry(node, struct drm_syncobj_wait_pt, node);
>> + node = rb_next(node);
>> + rb_erase(&wait_pt->node,
>> + &syncobj_timeline->wait_pt_tree);
>> + RB_CLEAR_NODE(&wait_pt->node);
>> + /* kfree(wait_pt) is excuted by fence put */
>> + dma_fence_put(&wait_pt->base.base);
>> + }
>> + list_for_each_entry_safe(signal_pt, tmp,
>> + &syncobj_timeline->signal_pt_list, list) {
>> + list_del(&signal_pt->list);
>> + dma_fence_put(signal_pt->signal_fence);
>> + dma_fence_put(signal_pt->pre_pt_base);
>> + dma_fence_put(&signal_pt->base.base);
>> + }
>> + spin_unlock(&syncobj->lock);
>> +}
>> +
>> /**
>> * drm_syncobj_free - free a sync object.
>> * @kref: kref to free.
>> @@ -261,10 +579,23 @@ void drm_syncobj_free(struct kref *kref)
>> struct drm_syncobj,
>> refcount);
>> drm_syncobj_replace_fence(syncobj, NULL, 0);
>> + drm_syncobj_timeline_fini(syncobj, &syncobj->syncobj_timeline);
>> kfree(syncobj);
>> }
>> EXPORT_SYMBOL(drm_syncobj_free);
>>
>> +static void drm_syncobj_timeline_init(struct drm_syncobj_timeline
>> + *syncobj_timeline)
>> +{
>> + syncobj_timeline->timeline_context = dma_fence_context_alloc(1);
>> + syncobj_timeline->timeline = 0;
>> + syncobj_timeline->signal_point = 0;
>> + init_waitqueue_head(&syncobj_timeline->wq);
>> +
>> + syncobj_timeline->wait_pt_tree = RB_ROOT;
>> + INIT_LIST_HEAD(&syncobj_timeline->signal_pt_list);
>> +}
>> +
>> /**
>> * drm_syncobj_create - create a new syncobj
>> * @out_syncobj: returned syncobj
>> @@ -290,6 +621,12 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags,
>> kref_init(&syncobj->refcount);
>> INIT_LIST_HEAD(&syncobj->cb_list);
>> spin_lock_init(&syncobj->lock);
>> + if (flags & DRM_SYNCOBJ_CREATE_TYPE_TIMELINE) {
>> + syncobj->type = DRM_SYNCOBJ_TYPE_TIMELINE;
>> + drm_syncobj_timeline_init(&syncobj->syncobj_timeline);
>> + } else {
>> + syncobj->type = DRM_SYNCOBJ_TYPE_NORMAL;
>> + }
>>
>> if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) {
>> ret = drm_syncobj_assign_null_handle(syncobj);
>> diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h
>> index 335ec501001a..342b3ced3e56 100644
>> --- a/include/drm/drm_syncobj.h
>> +++ b/include/drm/drm_syncobj.h
>> @@ -30,6 +30,25 @@
>>
>> struct drm_syncobj_cb;
>>
>> +enum drm_syncobj_type {
>> + DRM_SYNCOBJ_TYPE_NORMAL,
>> + DRM_SYNCOBJ_TYPE_TIMELINE
>> +};
>> +
>> +struct drm_syncobj_timeline {
>> + wait_queue_head_t wq;
>> + u64 timeline_context;
>> + /**
>> + * @timeline: syncobj timeline
>> + */
>> + u64 timeline;
>> + u64 signal_point;
>> +
>> +
>> + struct rb_root wait_pt_tree;
>> + struct list_head signal_pt_list;
>> +};
>> +
>> /**
>> * struct drm_syncobj - sync object.
>> *
>> @@ -40,6 +59,15 @@ struct drm_syncobj {
>> * @refcount: Reference count of this object.
>> */
>> struct kref refcount;
>> + /**
>> + * @type: indicate syncobj type
>> + */
>> + enum drm_syncobj_type type;
>> + /**
>> + * @syncobj_timeline: timeline
>> + */
>> + struct drm_syncobj_timeline syncobj_timeline;
>> +
>> /**
>> * @fence:
>> * NULL or a pointer to the fence bound to this object.
>> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
>> index 300f336633f2..cebdb2541eb7 100644
>> --- a/include/uapi/drm/drm.h
>> +++ b/include/uapi/drm/drm.h
>> @@ -717,6 +717,7 @@ struct drm_prime_handle {
>> struct drm_syncobj_create {
>> __u32 handle;
>> #define DRM_SYNCOBJ_CREATE_SIGNALED (1 << 0)
>> +#define DRM_SYNCOBJ_CREATE_TYPE_TIMELINE (1 << 1)
>> __u32 flags;
>> };
>>
>> --
>> 2.14.1
>>
