From 2d3e7b6e9a74d0a1a0ffe5733c5cea31baa59f41 Mon Sep 17 00:00:00 2001
From: Hans-Kristian Arntzen <post@arntzen-software.no>
Date: Tue, 27 Feb 2024 18:55:19 +0100
Subject: [PATCH] wsi/wl: Fix deadlock in dispatch_queue_timeout.

Signed-off-by: Hans-Kristian Arntzen <post@arntzen-software.no>
Fixes: a00f9c401b ("loader/wayland: Add fallback wl_display_dispatch_queue_timeout")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27828>
---
 src/loader/loader_wayland_helper.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/loader/loader_wayland_helper.c b/src/loader/loader_wayland_helper.c
index 4cb2da7d156..c25d787b68b 100644
--- a/src/loader/loader_wayland_helper.c
+++ b/src/loader/loader_wayland_helper.c
@@ -122,6 +122,12 @@ wl_display_dispatch_queue_timeout(struct wl_display *display,
       ret = wl_display_dispatch_queue_pending(display, queue);
       if (ret != 0)
          break;
+
+      /* wl_display_dispatch_queue_pending can return 0 if we ended up reading
+       * from WL fd, but there was no complete event to dispatch yet.
+       * Try reading again. */
+      if (wl_display_prepare_read_queue(display, queue) == -1)
+         return wl_display_dispatch_queue_pending(display, queue);
    }
 
    return ret;