[PATCH vkd3d 1/2] vkd3d: Handle NULL event handles in ID3D12Fence::SetEventOnCompletion().

[Conor McCarthy]

The D3D12 documentation states: "If hEvent is a null handle, then
this API will not return until the specified fence value(s) have
been reached."

Based on a vkd3d-proton patch by Hans-Kristian Arntzen.

Signed-off-by: Conor McCarthy 
---
 libs/vkd3d/command.c       | 39 ++++++++++++++++++++++++++++++++++++--
 libs/vkd3d/vkd3d_private.h |  2 ++
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/libs/vkd3d/command.c b/libs/vkd3d/command.c
index 9f4a4149..51a44704 100644
--- a/libs/vkd3d/command.c
+++ b/libs/vkd3d/command.c
@@ -805,6 +805,7 @@ static HRESULT d3d12_fence_signal(struct d3d12_fence *fence, uint64_t value, VkF
 {
     struct d3d12_device *device = fence->device;
     struct vkd3d_signaled_semaphore *current;
+    bool signal_null_event_cond = false;
     unsigned int i, j;
     int rc;

@@ -822,7 +823,15 @@ static HRESULT d3d12_fence_signal(struct d3d12_fence *fence, uint64_t value, VkF

if (current->value <= value)
         {
-            fence->device->signal_event(current->event);
+            if (current->event)
+            {
+                fence->device->signal_event(current->event);
+            }
+            else
+            {
+                current->latch = true;
+                signal_null_event_cond = true;
+            }
         }
         else
         {
@@ -833,6 +842,9 @@ static HRESULT d3d12_fence_signal(struct d3d12_fence *fence, uint64_t value, VkF
     }
     fence->event_count = j;

+    if (signal_null_event_cond)
+        pthread_cond_broadcast(&fence->null_event_cond);
+
     if (vk_fence)
     {
         const struct vkd3d_vk_device_procs *vk_procs = &device->vk_procs;
@@ -915,6 +927,7 @@ static ULONG STDMETHODCALLTYPE d3d12_fence_Release(ID3D12Fence *iface)
         vkd3d_free(fence->events);
         if ((rc = pthread_mutex_destroy(&fence->mutex)))
             ERR("Failed to destroy mutex, error %d.\n", rc);
+        pthread_cond_destroy(&fence->null_event_cond);
         vkd3d_free(fence);

d3d12_device_release(device);
@@ -996,6 +1009,7 @@ static HRESULT STDMETHODCALLTYPE d3d12_fence_SetEventOnCompletion(ID3D12Fence *i
 {
     struct d3d12_fence *fence = impl_from_ID3D12Fence(iface);
     unsigned int i;
+    bool volatile *latch;
     int rc;

TRACE("iface %p, value %#"PRIx64", event %p.\n", iface, value, event);
@@ -1008,7 +1022,8 @@ static HRESULT STDMETHODCALLTYPE d3d12_fence_SetEventOnCompletion(ID3D12Fence *i

if (value <= fence->value)
     {
-        fence->device->signal_event(event);
+        if (event)
+            fence->device->signal_event(event);
         pthread_mutex_unlock(&fence->mutex);
         return S_OK;
     }
@@ -1035,8 +1050,20 @@ static HRESULT STDMETHODCALLTYPE d3d12_fence_SetEventOnCompletion(ID3D12Fence *i

fence->events[fence->event_count].value = value;
     fence->events[fence->event_count].event = event;
+    fence->events[fence->event_count].latch = false;
+    latch = &fence->events[fence->event_count].latch;
     ++fence->event_count;

+    /* If event is NULL, we need to block until the fence value completes.
+     * Implement this in a uniform way where we pretend we have a dummy event.
+     * A NULL fence->events[].event means that we should set latch to true
+     * and signal a condition variable instead of calling external signal_event callback. */
+    if (!event)
+    {
+        while (!*latch)
+            pthread_cond_wait(&fence->null_event_cond, &fence->mutex);
+    }
+
     pthread_mutex_unlock(&fence->mutex);
     return S_OK;
 }
@@ -1094,6 +1121,13 @@ static HRESULT d3d12_fence_init(struct d3d12_fence *fence, struct d3d12_device *
         return hresult_from_errno(rc);
     }

+    if ((rc = pthread_cond_init(&fence->null_event_cond, NULL)))
+    {
+        ERR("Failed to initialize cond variable, error %d.\n", rc);
+        pthread_mutex_destroy(&fence->mutex);
+        return hresult_from_errno(rc);
+    }
+
     if (flags)
         FIXME("Ignoring flags %#x.\n", flags);

@@ -1111,6 +1145,7 @@ static HRESULT d3d12_fence_init(struct d3d12_fence *fence, struct d3d12_device *
     if (FAILED(hr = vkd3d_private_store_init(&fence->private_store)))
     {
         pthread_mutex_destroy(&fence->mutex);
+        pthread_cond_destroy(&fence->null_event_cond);
         return hr;
     }

diff --git a/libs/vkd3d/vkd3d_private.h b/libs/vkd3d/vkd3d_private.h
index 0b326b11..72682b15 100644
--- a/libs/vkd3d/vkd3d_private.h
+++ b/libs/vkd3d/vkd3d_private.h
@@ -334,11 +334,13 @@ struct d3d12_fence

uint64_t value;
     pthread_mutex_t mutex;
+    pthread_cond_t null_event_cond;

struct vkd3d_waiting_event
     {
         uint64_t value;
         HANDLE event;
+        bool volatile latch;
     } *events;
     size_t events_size;
     size_t event_count;