From cd8b90a7a7185c3f177469d1a37654a9e8539cd1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Thu, 29 Sep 2022 14:23:55 +0200
Subject: [PATCH 2/2] output/kms: Don't attemp to add common modes on
 connectors without modes

We have no way to sanely add safe modes if there are no modes we can
compare with, thus don't try.

Fixes the following crash:

 #0 are_all_modes_equally_sized at ../src/backends/native/meta-output-kms.c:284
 #1 maybe_add_fallback_modes at ../src/backends/native/meta-output-kms.c:310
 #2 init_output_modes at ../src/backends/native/meta-output-kms.c:347
 #3 meta_output_kms_new at ../src/backends/native/meta-output-kms.c:414
 #4 init_outputs at ../src/backends/native/meta-gpu-kms.c:332
 #5 meta_gpu_kms_read_current at ../src/backends/native/meta-gpu-kms.c:368
 #6 meta_gpu_kms_new at ../src/backends/native/meta-gpu-kms.c:403
 #7 create_gpu_from_udev_device at ../src/backends/native/meta-backend-native.c:461
 #8 init_gpus at ../src/backends/native/meta-backend-native.c:551
 #9 meta_backend_native_initable_init at ../src/backends/native/meta-backend-native.c:632

Fixes: 877cc3eb7d44e2886395151f763ec09bea350444
Related: https://bugzilla.redhat.com/show_bug.cgi?id=2127801
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2646>
(cherry picked from commit 2c8adb19660cb2cd53381372833e088962437d3b)
---
 src/backends/native/meta-output-kms.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/backends/native/meta-output-kms.c b/src/backends/native/meta-output-kms.c
index 9adc20bfd9..058ab7c053 100644
--- a/src/backends/native/meta-output-kms.c
+++ b/src/backends/native/meta-output-kms.c
@@ -250,6 +250,9 @@ maybe_add_fallback_modes (const MetaKmsConnectorState *connector_state,
                           MetaGpuKms                  *gpu_kms,
                           MetaKmsConnector            *kms_connector)
 {
+  if (!connector_state->modes)
+    return;
+
   if (!connector_state->has_scaling)
     return;
 
-- 
2.37.1