vulkan/wsi/x11: wait for acquirable images in FIFO mode

In FIFO presentation mode we block either on our present-queue or on Present
events after an image was transmitted.

In case we receive completion events without idle events at some point we
exhaust our acquire-queue and can not block anymore on present-queue.

Ensure that the consumer has at least one image to acquire before blocking
again on present-queue. Otherwise wait for one from the X server.

CC: mesa-stable
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/3344
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Simon Ser <contact@emersion.fr>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6513>

diff --git a/src/vulkan/wsi/wsi_common_x11.c b/src/vulkan/wsi/wsi_common_x11.c
index 2be3072587a8abfd7be6cb26ded871ea436707c2..961704f2057d49127e5320c40d793a8e70988d63 100644 (file)
--- a/src/vulkan/wsi/wsi_common_x11.c
+++ b/src/vulkan/wsi/wsi_common_x11.c
@@ -1145,11 +1145,9 @@ x11_manage_fifo_queues(void *state)
 
    assert(chain->has_present_queue);
    while (chain->status >= 0) {
-      /* It should be safe to unconditionally block here.  Later in the loop
-       * we blocks until the previous present has landed on-screen.  At that
-       * point, we should have received IDLE_NOTIFY on all images presented
-       * before that point so the client should be able to acquire any image
-       * other than the currently presented one.
+      /* We can block here unconditionally because after an image was sent to
+       * the server (later on in this loop) we ensure at least one image is
+       * acquirable by the consumer or wait there on such an event.
        */
       uint32_t image_index = 0;
       result = wsi_queue_pull(&chain->present_queue, &image_index, INT64_MAX);
@@ -1182,7 +1180,12 @@ x11_manage_fifo_queues(void *state)
          goto fail;
 
       if (chain->has_acquire_queue) {
-         while (chain->last_present_msc < target_msc) {
+         /* Wait for our presentation to occur and ensure we have at least one
+          * image that can be acquired by the client afterwards. This ensures we
+          * can pull on the present-queue on the next loop.
+          */
+         while (chain->last_present_msc < target_msc ||
+                chain->sent_image_count == chain->base.image_count) {
             xcb_generic_event_t *event =
                xcb_wait_for_special_event(chain->conn, chain->special_event);
             if (!event) {