From 2a16a750c556a916a6792adf10adbe4499d5e092 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Tue, 7 Dec 2021 22:12:57 +0100
Subject: [PATCH] wayland/dma-buf: Always advertise non-modifier fallback

This is done to explicitly tell clients that the compositor supports
implicit modifier paths (i.e. using modifier unaware API).

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1959>
---
 src/wayland/meta-wayland-dma-buf.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/wayland/meta-wayland-dma-buf.c b/src/wayland/meta-wayland-dma-buf.c
index c41577f9d..c194a35ff 100644
--- a/src/wayland/meta-wayland-dma-buf.c
+++ b/src/wayland/meta-wayland-dma-buf.c
@@ -868,12 +868,18 @@ should_send_modifiers (MetaBackend *backend)
 
 static void
 send_modifiers (struct wl_resource      *resource,
-                MetaWaylandDmaBufFormat *format)
+                MetaWaylandDmaBufFormat *format,
+                GHashTable              *sent_formats)
 {
   g_assert (wl_resource_get_version (resource) <
             ZWP_LINUX_DMABUF_V1_GET_DEFAULT_FEEDBACK_SINCE_VERSION);
 
-  zwp_linux_dmabuf_v1_send_format (resource, format->drm_format);
+  if (!g_hash_table_contains (sent_formats,
+                              GUINT_TO_POINTER (format->drm_format)))
+    {
+      g_hash_table_add (sent_formats, GUINT_TO_POINTER (format->drm_format));
+      zwp_linux_dmabuf_v1_send_format (resource, format->drm_format);
+    }
 
   if (wl_resource_get_version (resource) <
       ZWP_LINUX_DMABUF_V1_MODIFIER_SINCE_VERSION)
@@ -901,8 +907,11 @@ dma_buf_bind (struct wl_client *client,
 
   if (version < ZWP_LINUX_DMABUF_V1_GET_DEFAULT_FEEDBACK_SINCE_VERSION)
     {
+      g_autoptr (GHashTable) sent_formats = NULL;
       unsigned int i;
 
+      sent_formats = g_hash_table_new (NULL, NULL);
+
       for (i = 0; i < dma_buf_manager->formats->len; i++)
         {
           MetaWaylandDmaBufFormat *format =
@@ -910,7 +919,7 @@ dma_buf_bind (struct wl_client *client,
                             MetaWaylandDmaBufFormat,
                             i);
 
-          send_modifiers (resource, format);
+          send_modifiers (resource, format, sent_formats);
         }
     }
 }
@@ -961,8 +970,6 @@ add_format (MetaWaylandDmaBufManager *dma_buf_manager,
       g_array_append_val (dma_buf_manager->formats, format);
     }
 
-  return;
-
 add_fallback:
   format = (MetaWaylandDmaBufFormat) {
     .drm_format = drm_format,