diff --git a/src/config.c b/src/config.c
index 316438e..2299039 100644
--- a/src/config.c
+++ b/src/config.c
@@ -623,11 +623,13 @@ struct debug_options_entry {
 	size_t offset;
 };
 
+// clang-format off
+static const char *vblank_scheduler_choices[] = { "present", "sgi_video_sync", NULL };
 static const struct debug_options_entry debug_options_entries[] = {
-    "smart_frame_pacing",
-    NULL,
-    offsetof(struct debug_options, smart_frame_pacing),
+    {"smart_frame_pacing", NULL,                     offsetof(struct debug_options, smart_frame_pacing)},
+    {"force_vblank_sched", vblank_scheduler_choices, offsetof(struct debug_options, force_vblank_scheduler)},
 };
+// clang-format on
 
 void parse_debug_option_single(char *setting, struct debug_options *debug_options) {
 	char *equal = strchr(setting, '=');
@@ -667,7 +669,9 @@ void parse_debug_option_single(char *setting, struct debug_options *debug_option
 /// Parse debug options from environment variable `PICOM_DEBUG`.
 void parse_debug_options(struct debug_options *debug_options) {
 	const char *debug = getenv("PICOM_DEBUG");
-	const struct debug_options default_debug_options = {};
+	const struct debug_options default_debug_options = {
+	    .force_vblank_scheduler = LAST_VBLANK_SCHEDULER,
+	};
 
 	*debug_options = default_debug_options;
 	if (!debug) {
diff --git a/src/config.h b/src/config.h
index b414b9a..760088c 100644
--- a/src/config.h
+++ b/src/config.h
@@ -88,6 +88,8 @@ struct debug_options {
 	/// Try to reduce frame latency by using vblank interval and render time
 	/// estimates. Right now it's not working well across drivers.
 	int smart_frame_pacing;
+	/// Override the vblank scheduler chosen by the compositor.
+	int force_vblank_scheduler;
 };
 
 /// Structure representing all options.
diff --git a/src/picom.c b/src/picom.c
index 9ca6c96..819a924 100644
--- a/src/picom.c
+++ b/src/picom.c
@@ -1489,9 +1489,13 @@ static bool redirect_start(session_t *ps) {
 		ps->last_msc = 0;
 		ps->last_schedule_delay = 0;
 		render_statistics_reset(&ps->render_stats);
-		ps->vblank_scheduler =
-		    vblank_scheduler_new(ps->loop, &ps->c, session_get_target_window(ps),
-		                         PRESENT_VBLANK_SCHEDULER);
+		enum vblank_scheduler_type scheduler_type = PRESENT_VBLANK_SCHEDULER;
+		if (ps->o.debug_options.force_vblank_scheduler != LAST_VBLANK_SCHEDULER) {
+			scheduler_type =
+			    (enum vblank_scheduler_type)ps->o.debug_options.force_vblank_scheduler;
+		}
+		ps->vblank_scheduler = vblank_scheduler_new(
+		    ps->loop, &ps->c, session_get_target_window(ps), scheduler_type);
 		if (!ps->vblank_scheduler) {
 			return false;
 		}