From c5c4360da7d776a3722698a01e9b4479fdb656e9 Mon Sep 17 00:00:00 2001
From: Alessandro Astone <ales.astone@gmail.com>
Date: Thu, 28 Dec 2023 20:11:07 +0100
Subject: [PATCH] Disable zink fallback in EGL

In mesa 23.3.x zink broke on nvidia, crashing in eglCreateContext.
In the same release, zink was added as a fallback between the
hardware drivers and swrast.
Any application that was previously falling back to swrast
now instead crashes, when using the nvidia vulkan driver.

How exactly do you reach zink or previously swrast when using
nvidia you may ask?
One common path may be EGL applications using EGL_EXT_platform_xcb.
The nvidia driver does not support it, thus GLVND tries the next
driver which is mesa, mesa doesn't find any suitable hardware driver
and thus falls back to zink or swrast.

Until zink is stable again on nvidia, we should disable the zink
fallback to prevent applications crashing instead of falling back
to swrast.

There should be no need to also disable the GLX fallback to zink
as i'm not aware of a call path that would lead to using mesa when
the nvidia drivers are installed.

RHBZ 2255599
RHBZ 2255768
MESA 10340
MESA 10341
---
 disable-zink-egl-fallback.patch | 26 ++++++++++++++++++++++++++
 mesa.spec                       |  1 +
 2 files changed, 27 insertions(+)
 create mode 100644 disable-zink-egl-fallback.patch

diff --git a/disable-zink-egl-fallback.patch b/disable-zink-egl-fallback.patch
new file mode 100644
index 0000000..c036ace
--- /dev/null
+++ b/disable-zink-egl-fallback.patch
@@ -0,0 +1,26 @@
+diff --git a/src/egl/main/eglapi.c b/src/egl/main/eglapi.c
+index d50be23e871..e3697622635 100644
+--- a/src/egl/main/eglapi.c
++++ b/src/egl/main/eglapi.c
+@@ -695,17 +695,21 @@ eglInitialize(EGLDisplay dpy, EGLint *major, EGLint *minor)
+          if (disp->Options.ForceSoftware)
+             RETURN_EGL_ERROR(disp, EGL_NOT_INITIALIZED, EGL_FALSE);
+          else {
++#if 0
+             bool success = false;
+             if (!disp->Options.Zink && !getenv("GALLIUM_DRIVER")) {
+                disp->Options.Zink = EGL_TRUE;
+                success = _eglDriver.Initialize(disp);
+             }
+             if (!success) {
++#endif
+                disp->Options.Zink = EGL_FALSE;
+                disp->Options.ForceSoftware = EGL_TRUE;
+                if (!_eglDriver.Initialize(disp))
+                   RETURN_EGL_ERROR(disp, EGL_NOT_INITIALIZED, EGL_FALSE);
++#if 0
+             }
++#endif
+          }
+       }
+ 
diff --git a/mesa.spec b/mesa.spec
index f50fd34..3cedbdc 100644
--- a/mesa.spec
+++ b/mesa.spec
@@ -76,6 +76,7 @@ Source1:        Mesa-MLAA-License-Clarification-Email.txt
 Patch10:        gnome-shell-glthread-disable.patch
 Patch11:        0001-intel-compiler-reemit-boolean-resolve-for-inverted-i.patch
 Patch12:        0001-intel-compiler-fix-release-build-unused-variable.patch
+Patch13:        disable-zink-egl-fallback.patch
 
 BuildRequires:  meson >= 1.2.0
 BuildRequires:  gcc