From 8cd44b8843877a2f7d559d123eb3694841f16fdc Mon Sep 17 00:00:00 2001
From: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Date: Mon, 9 Oct 2023 15:02:13 -0400
Subject: [PATCH] egl: add automatic zink fallback loading between hw and sw
 drivers

if loading the default hardware driver fails, implicitly loading zink
should now be preferable to hitting the software fallback now that zink
has all the same capabilities

Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25640>
---
 src/egl/main/eglapi.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/egl/main/eglapi.c b/src/egl/main/eglapi.c
index b1a48668b76..b9f179c2ce3 100644
--- a/src/egl/main/eglapi.c
+++ b/src/egl/main/eglapi.c
@@ -695,10 +695,17 @@ eglInitialize(EGLDisplay dpy, EGLint *major, EGLint *minor)
          if (disp->Options.ForceSoftware)
             RETURN_EGL_ERROR(disp, EGL_NOT_INITIALIZED, EGL_FALSE);
          else {
-            disp->Options.Zink = EGL_FALSE;
-            disp->Options.ForceSoftware = EGL_TRUE;
-            if (!_eglDriver.Initialize(disp))
-               RETURN_EGL_ERROR(disp, EGL_NOT_INITIALIZED, EGL_FALSE);
+            bool success = disp->Options.Zink;
+            if (!disp->Options.Zink && !getenv("GALLIUM_DRIVER")) {
+               disp->Options.Zink = EGL_TRUE;
+               success = _eglDriver.Initialize(disp);
+            }
+            if (!success) {
+               disp->Options.Zink = EGL_FALSE;
+               disp->Options.ForceSoftware = EGL_TRUE;
+               if (!_eglDriver.Initialize(disp))
+                  RETURN_EGL_ERROR(disp, EGL_NOT_INITIALIZED, EGL_FALSE);
+            }
          }
       }