vulkan/overlay: Add a workaround semaphore for application presenting without one

When an application calls vkQueuePresent() on a different queue than
the one we run our drawing on and it doesn't give a semaphore to wait
on, let's insert our own semaphore so that we don't race the
application's drawing.

Signed-off-by: Lionel Landwerlin <[email protected]>
Closes: https://gitlab.freedesktop.org/mesa/mesa/issues/2540
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3893>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3893>

1 files changed, 53 insertions, 19 deletions

diff --git a/src/vulkan/overlay-layer/overlay.cpp b/src/vulkan/overlay-layer/overlay.cpp
index 565f5884bb6..1ed1d2b02e7 100644
--- a/src/vulkan/overlay-layer/overlay.cpp
+++ b/src/vulkan/overlay-layer/overlay.cpp
@@ -125,6 +125,8 @@ struct overlay_draw {
 
    VkCommandBuffer command_buffer;
 
+   VkSemaphore cross_engine_semaphore;
+
    VkSemaphore semaphore;
    VkFence fence;
 
@@ -544,6 +546,8 @@ struct overlay_draw *get_overlay_draw(struct swapchain_data *data)
 
    VK_CHECK(device_data->vtable.CreateSemaphore(device_data->device, &sem_info,
                                                 NULL, &draw->semaphore));
+   VK_CHECK(device_data->vtable.CreateSemaphore(device_data->device, &sem_info,
+                                                NULL, &draw->cross_engine_semaphore));
 
    list_addtail(&draw->link, &data->draws);
 
@@ -1349,26 +1353,55 @@ static struct overlay_draw *render_swapchain_display(struct swapchain_data *data
 
    device_data->vtable.EndCommandBuffer(draw->command_buffer);
 
-   VkPipelineStageFlags *stages_wait = (VkPipelineStageFlags*) malloc(sizeof(VkPipelineStageFlags) * n_wait_semaphores);
-   for (unsigned i = 0; i < n_wait_semaphores; i++)
-   {
-      // wait in the fragment stage until the swapchain image is ready
-      stages_wait[i] = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT;
+   /* When presenting on a different queue than where we're drawing the
+    * overlay *AND* when the application does not provide a semaphore to
+    * vkQueuePresent, insert our own cross engine synchronization
+    * semaphore.
+    */
+   if (n_wait_semaphores == 0 && device_data->graphic_queue->queue != present_queue->queue) {
+      VkPipelineStageFlags stages_wait = VK_PIPELINE_STAGE_ALL_COMMANDS_BIT;
+      VkSubmitInfo submit_info = {};
+      submit_info.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
+      submit_info.commandBufferCount = 0;
+      submit_info.pWaitDstStageMask = &stages_wait;
+      submit_info.waitSemaphoreCount = 0;
+      submit_info.signalSemaphoreCount = 1;
+      submit_info.pSignalSemaphores = &draw->cross_engine_semaphore;
+
+      device_data->vtable.QueueSubmit(present_queue->queue, 1, &submit_info, VK_NULL_HANDLE);
+
+      submit_info.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
+      submit_info.commandBufferCount = 1;
+      submit_info.pWaitDstStageMask = &stages_wait;
+      submit_info.pCommandBuffers = &draw->command_buffer;
+      submit_info.waitSemaphoreCount = 1;
+      submit_info.pWaitSemaphores = &draw->cross_engine_semaphore;
+      submit_info.signalSemaphoreCount = 1;
+      submit_info.pSignalSemaphores = &draw->semaphore;
+
+      device_data->vtable.QueueSubmit(device_data->graphic_queue->queue, 1, &submit_info, draw->fence);
+   } else {
+      VkPipelineStageFlags *stages_wait = (VkPipelineStageFlags*) malloc(sizeof(VkPipelineStageFlags) * n_wait_semaphores);
+      for (unsigned i = 0; i < n_wait_semaphores; i++)
+      {
+         // wait in the fragment stage until the swapchain image is ready
+         stages_wait[i] = VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT;
+      }
+
+      VkSubmitInfo submit_info = {};
+      submit_info.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
+      submit_info.commandBufferCount = 1;
+      submit_info.pCommandBuffers = &draw->command_buffer;
+      submit_info.pWaitDstStageMask = stages_wait;
+      submit_info.waitSemaphoreCount = n_wait_semaphores;
+      submit_info.pWaitSemaphores = wait_semaphores;
+      submit_info.signalSemaphoreCount = 1;
+      submit_info.pSignalSemaphores = &draw->semaphore;
+
+      device_data->vtable.QueueSubmit(device_data->graphic_queue->queue, 1, &submit_info, draw->fence);
+
+      free(stages_wait);
    }
-   
-   VkSubmitInfo submit_info = {};
-   submit_info.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
-   submit_info.commandBufferCount = 1;
-   submit_info.pCommandBuffers = &draw->command_buffer;
-   submit_info.pWaitDstStageMask = stages_wait;
-   submit_info.waitSemaphoreCount = n_wait_semaphores;
-   submit_info.pWaitSemaphores = wait_semaphores;
-   submit_info.signalSemaphoreCount = 1;
-   submit_info.pSignalSemaphores = &draw->semaphore;
-
-   device_data->vtable.QueueSubmit(device_data->graphic_queue->queue, 1, &submit_info, draw->fence);
-   
-   free(stages_wait);
 
    return draw;
 }
@@ -1750,6 +1783,7 @@ static void shutdown_swapchain_data(struct swapchain_data *data)
    struct device_data *device_data = data->device;
 
    list_for_each_entry_safe(struct overlay_draw, draw, &data->draws, link) {
+      device_data->vtable.DestroySemaphore(device_data->device, draw->cross_engine_semaphore, NULL);
       device_data->vtable.DestroySemaphore(device_data->device, draw->semaphore, NULL);
       device_data->vtable.DestroyFence(device_data->device, draw->fence, NULL);
       device_data->vtable.DestroyBuffer(device_data->device, draw->vertex_buffer, NULL);