From ecbe4a5dada65ca8c753ddb1e9ed43257a89a2e1 Mon Sep 17 00:00:00 2001
From: Mario Limonciello <mario.limonciello@amd.com>
Date: Wed, 6 Nov 2024 13:54:55 -0600
Subject: [PATCH] Prefer GPUs with built-in panels connected when selecting a
 primary GPU
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Some laptops don't have the integrated GPU come earlier in the PCI topology
which means that when mutter enumerates the GPUs it may select the dGPU
as the primary.

In a laptop context, this is unlikely to work because the eDP panel can
only be actively connected to a single GPU at a time.

Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/3746
Suggested-by: Jonas Ådahl
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4114>
---
 src/backends/native/meta-kms-device.c      | 24 ++++++++++++++++++++++
 src/backends/native/meta-kms-device.h      |  2 ++
 src/backends/native/meta-renderer-native.c | 15 ++++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/src/backends/native/meta-kms-device.c b/src/backends/native/meta-kms-device.c
index b3fcc71bd..a04ad1e08 100644
--- a/src/backends/native/meta-kms-device.c
+++ b/src/backends/native/meta-kms-device.c
@@ -849,3 +849,27 @@ meta_kms_device_class_init (MetaKmsDeviceClass *klass)
                   G_TYPE_NONE, 1,
                   META_TYPE_KMS_CRTC);
 }
+
+gboolean
+meta_kms_device_has_connected_builtin_panel (MetaKmsDevice *device)
+{
+  GList *l;
+
+  for (l = device->connectors; l; l = l->next)
+    {
+      MetaKmsConnector *connector = META_KMS_CONNECTOR (l->data);
+
+      if (!meta_kms_connector_get_current_state (connector))
+        continue;
+
+      switch (meta_kms_connector_get_connector_type (connector))
+        {
+        case DRM_MODE_CONNECTOR_LVDS:
+        case DRM_MODE_CONNECTOR_eDP:
+        case DRM_MODE_CONNECTOR_DSI:
+          return TRUE;
+        }
+    }
+
+  return FALSE;
+}
diff --git a/src/backends/native/meta-kms-device.h b/src/backends/native/meta-kms-device.h
index 0b39f7df5..6dfa5a76a 100644
--- a/src/backends/native/meta-kms-device.h
+++ b/src/backends/native/meta-kms-device.h
@@ -107,3 +107,5 @@ MetaKmsDevice * meta_kms_device_new (MetaKms            *kms,
                                      const char         *path,
                                      MetaKmsDeviceFlag   flags,
                                      GError            **error);
+
+gboolean meta_kms_device_has_connected_builtin_panel (MetaKmsDevice *device);
diff --git a/src/backends/native/meta-renderer-native.c b/src/backends/native/meta-renderer-native.c
index 3bf7522c2..02451e2f1 100644
--- a/src/backends/native/meta-renderer-native.c
+++ b/src/backends/native/meta-renderer-native.c
@@ -2205,6 +2205,21 @@ choose_primary_gpu_unchecked (MetaBackend        *backend,
             }
         }
 
+      /* Then prefer a GPU with a builtin panel connected to it. */
+      for (l = gpus; l; l = l->next)
+        {
+          MetaGpuKms *gpu_kms = META_GPU_KMS (l->data);
+          MetaKmsDevice *kms_device = meta_gpu_kms_get_kms_device (gpu_kms);
+
+          if (meta_kms_device_has_connected_builtin_panel (kms_device) &&
+              (allow_sw == 1 ||
+               gpu_kms_is_hardware_rendering (renderer_native, gpu_kms)))
+            {
+              g_message ("GPU %s selected primary from builtin panel presence",
+                         meta_gpu_kms_get_file_path (gpu_kms));
+              return gpu_kms;
+            }
+        }
 
       /* Prefer a platform device */
       for (l = gpus; l; l = l->next)