mutter/SOURCES/0001-output-kms-Add-more-heuristics-to-decide-when-to-off.patch

From cf16c0d16b42215f35dcede6163235ad5ec1734b Mon Sep 17 00:00:00 2001
From: Mario Limonciello <mario.limonciello@amd.com>
Date: Thu, 18 Aug 2022 13:36:20 -0500
Subject: [PATCH] output/kms: Add more heuristics to decide when to offer
 fallback modes

If the panel is connected via eDP and supports more than one mode
at different resolutions don't try to add more.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2586>
(cherry picked from commit 96aa0fb8536eca579ceb1b17d83e19cf9e3e9e81)
---
 src/backends/native/meta-output-kms.c | 45 ++++++++++++++++++++++-----
 1 file changed, 38 insertions(+), 7 deletions(-)

diff --git a/src/backends/native/meta-output-kms.c b/src/backends/native/meta-output-kms.c
index f3cc543c4d..44c25c5648 100644
--- a/src/backends/native/meta-output-kms.c
+++ b/src/backends/native/meta-output-kms.c
@@ -505,6 +505,43 @@ compare_modes (const void *one,
   return g_strcmp0 (b->name, a->name);
 }
 
+static gboolean
+are_all_modes_equally_sized (MetaOutput *output)
+{
+  MetaCrtcMode *base = output->modes[0];
+  int i;
+
+  for (i = 1; i < output->n_modes; i++)
+    {
+      MetaCrtcMode *crtc_mode = output->modes[i];
+
+      if (base->width != crtc_mode->width ||
+          base->height != crtc_mode->height)
+        return FALSE;
+    }
+
+  return TRUE;
+}
+
+static void
+maybe_add_fallback_modes (MetaOutput *output,
+                          MetaGpuKms *gpu_kms)
+{
+  MetaOutputKms *output_kms = output->driver_private;
+
+  if (!output_kms->has_scaling)
+    return;
+
+  if (output->n_modes == 0)
+    return;
+
+  if (output_kms->connector->connector_type == DRM_MODE_CONNECTOR_eDP &&
+      !are_all_modes_equally_sized (output))
+    return;
+
+  add_common_modes (output, gpu_kms);
+}
+
 static gboolean
 init_output_modes (MetaOutput  *output,
                    MetaGpuKms  *gpu_kms,
@@ -528,13 +565,7 @@ init_output_modes (MetaOutput  *output,
         output->preferred_mode = output->modes[i];
     }
 
-  /* FIXME: MSC feature bit? */
-  /* Presume that if the output supports scaling, then we have
-   * a panel fitter capable of adjusting any mode to suit.
-   */
-  if (output_kms->has_scaling)
-    add_common_modes (output, gpu_kms);
-
+  maybe_add_fallback_modes (output, gpu_kms);
   if (!output->modes)
     {
       g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
-- 
2.37.1