From cc32c5c2eb02e2ba8a7dd5463ee46893b7978c47 Mon Sep 17 00:00:00 2001
From: Karol Herbst <kherbst@redhat.com>
Date: Mon, 7 Jul 2025 13:27:10 +0200
Subject: [PATCH] gallium: add pipe_screen::semaphore_create

Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36007>
---
 .../auxiliary/driver_ddebug/dd_screen.c       |  9 +++++++++
 src/gallium/auxiliary/driver_noop/noop_pipe.c | 10 ++++++++++
 .../auxiliary/driver_trace/tr_screen.c        | 20 +++++++++++++++++++
 src/gallium/include/pipe/p_screen.h           |  8 ++++++++
 4 files changed, 47 insertions(+)

diff --git a/src/gallium/auxiliary/driver_ddebug/dd_screen.c b/src/gallium/auxiliary/driver_ddebug/dd_screen.c
index 6c427eb882d..becc8410719 100644
--- a/src/gallium/auxiliary/driver_ddebug/dd_screen.c
+++ b/src/gallium/auxiliary/driver_ddebug/dd_screen.c
@@ -453,6 +453,14 @@ dd_screen_memobj_destroy(struct pipe_screen *_screen,
 
    screen->memobj_destroy(screen, memobj);
 }
+
+static struct pipe_fence_handle *
+dd_screen_semaphore_create(struct pipe_screen *_screen)
+{
+   struct pipe_screen *screen = dd_screen(_screen)->screen;
+
+   return screen->semaphore_create(screen);
+}
 /********************************************************************
  * screen
  */
@@ -664,6 +672,7 @@ ddebug_screen_create(struct pipe_screen *screen)
    dscreen->base.get_driver_pipe_screen = dd_get_driver_pipe_screen;
    SCR_INIT(is_dmabuf_modifier_supported);
    SCR_INIT(get_dmabuf_modifier_planes);
+   SCR_INIT(semaphore_create);
 
    /* copy all caps */
    *(struct pipe_caps *)&dscreen->base.caps = screen->caps;
diff --git a/src/gallium/auxiliary/driver_noop/noop_pipe.c b/src/gallium/auxiliary/driver_noop/noop_pipe.c
index 4845068a67e..a8c1c13433d 100644
--- a/src/gallium/auxiliary/driver_noop/noop_pipe.c
+++ b/src/gallium/auxiliary/driver_noop/noop_pipe.c
@@ -736,6 +736,14 @@ static void noop_vertex_state_destroy(struct pipe_screen *screen,
    FREE(state);
 }
 
+static struct pipe_fence_handle *
+noop_semaphore_create(struct pipe_screen *screen)
+{
+   struct pipe_reference *f = MALLOC_STRUCT(pipe_reference);
+   f->count = 1;
+   return (struct pipe_fence_handle*)f;
+}
+
 static struct pipe_screen * noop_get_driver_pipe_screen(struct pipe_screen *_screen)
 {
    struct pipe_screen * screen = ((struct noop_pipe_screen*)_screen)->oscreen;
@@ -800,6 +808,8 @@ struct pipe_screen *noop_screen_create(struct pipe_screen *oscreen)
    screen->query_compression_rates = noop_query_compression_rates;
    screen->query_compression_modifiers = noop_query_compression_modifiers;
    screen->get_driver_pipe_screen = noop_get_driver_pipe_screen;
+   if (oscreen->semaphore_create)
+      screen->semaphore_create = noop_semaphore_create;
 
    /* copy all caps */
    *(struct pipe_caps *)&screen->caps = oscreen->caps;
diff --git a/src/gallium/auxiliary/driver_trace/tr_screen.c b/src/gallium/auxiliary/driver_trace/tr_screen.c
index 14171a350dc..7f4b103b9dd 100644
--- a/src/gallium/auxiliary/driver_trace/tr_screen.c
+++ b/src/gallium/auxiliary/driver_trace/tr_screen.c
@@ -936,6 +936,25 @@ trace_screen_fence_reference(struct pipe_screen *_screen,
 }
 
 
+static struct pipe_fence_handle *
+trace_screen_semaphore_create(struct pipe_screen *_screen)
+{
+   struct trace_screen *tr_scr = trace_screen(_screen);
+   struct pipe_screen *screen = tr_scr->screen;
+   struct pipe_fence_handle *res;
+
+   trace_dump_call_begin("pipe_screen", "fence_reference");
+   trace_dump_arg(ptr, screen);
+
+   res = screen->semaphore_create(screen);
+
+   trace_dump_ret(ptr, res);
+   trace_dump_call_end();
+
+   return res;
+}
+
+
 static int
 trace_screen_fence_get_fd(struct pipe_screen *_screen,
                           struct pipe_fence_handle *fence)
@@ -1508,6 +1527,7 @@ trace_screen_create(struct pipe_screen *screen)
    SCR_INIT(resource_changed);
    tr_scr->base.resource_destroy = trace_screen_resource_destroy;
    tr_scr->base.fence_reference = trace_screen_fence_reference;
+   SCR_INIT(semaphore_create);
    SCR_INIT(fence_get_fd);
    SCR_INIT(create_fence_win32);
    tr_scr->base.fence_finish = trace_screen_fence_finish;
diff --git a/src/gallium/include/pipe/p_screen.h b/src/gallium/include/pipe/p_screen.h
index 6d6f6548ef1..7eb97885f57 100644
--- a/src/gallium/include/pipe/p_screen.h
+++ b/src/gallium/include/pipe/p_screen.h
@@ -388,6 +388,14 @@ struct pipe_screen {
                            struct pipe_fence_handle **ptr,
                            struct pipe_fence_handle *fence);
 
+   /**
+    * Creates a semaphore that can be signaled and waited on through
+    * fence_server_sync and fence_server_signal.
+    *
+    * Drivers are required to not flush or wait on anything in this call.
+    */
+   struct pipe_fence_handle* (*semaphore_create)(struct pipe_screen *screen);
+
    /**
     * Wait for the fence to finish.
     *