From cb59480be00a28bbd7462df6abd17d4c752121f0 Mon Sep 17 00:00:00 2001
From: Joshua Ashton <joshua@froggi.es>
Date: Wed, 17 Aug 2022 02:01:46 +0000
Subject: [PATCH] drm: Add backdoor to disable liftoff caching for debugging

---
 src/drm.cpp | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/drm.cpp b/src/drm.cpp
index afba0f3..93d826e 100644
--- a/src/drm.cpp
+++ b/src/drm.cpp
@@ -1445,6 +1445,20 @@ LiftoffStateCacheEntry FrameInfoToLiftoffStateCacheEntry( const FrameInfo_t *fra
 	return entry;
 }
 
+static bool env_to_bool(const char *env)
+{
+	if (!env || !*env)
+		return false;
+
+	return !!atoi(env);
+}
+
+static bool is_liftoff_caching_enabled()
+{
+	static bool disabled = env_to_bool(getenv("GAMESCOPE_LIFTOFF_CACHE_DISABLE"));
+	return !disabled;
+}
+
 static int
 drm_prepare_liftoff( struct drm_t *drm, const struct FrameInfo_t *frameInfo, bool needs_modeset )
 {
@@ -1456,8 +1470,11 @@ drm_prepare_liftoff( struct drm_t *drm, const struct FrameInfo_t *frameInfo, boo
 	if (needs_modeset)
 		g_LiftoffStateCache.clear();
 
-	if (g_LiftoffStateCache.count(entry) != 0)
-		return -EINVAL;
+	if (is_liftoff_caching_enabled())
+	{
+		if (g_LiftoffStateCache.count(entry) != 0)
+			return -EINVAL;
+	}
 
 	for ( int i = 0; i < k_nMaxLayers; i++ )
 	{