From 3aed24b8d4572eb4cd2488113f1c1a23ceb290d8 Mon Sep 17 00:00:00 2001
From: Alexander Orzechowski <alex@ozal.ski>
Date: Fri, 17 Nov 2023 13:49:18 -0500
Subject: [PATCH] backend/drm: Track page flips in list

---
 backend/drm/backend.c     |  1 +
 backend/drm/drm.c         | 14 ++++++++++++--
 include/backend/drm/drm.h |  3 +++
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/backend/drm/backend.c b/backend/drm/backend.c
index e6c709bf..5ff2b90c 100644
--- a/backend/drm/backend.c
+++ b/backend/drm/backend.c
@@ -207,6 +207,7 @@ struct wlr_backend *wlr_drm_backend_create(struct wl_display *display,
 	drm->session = session;
 	wl_list_init(&drm->fbs);
 	wl_list_init(&drm->connectors);
+	wl_list_init(&drm->page_flips);
 
 	drm->dev = dev;
 	drm->fd = dev->fd;
diff --git a/backend/drm/drm.c b/backend/drm/drm.c
index 92feed6c..eb9e8267 100644
--- a/backend/drm/drm.c
+++ b/backend/drm/drm.c
@@ -420,6 +420,15 @@ static void drm_connector_set_pending_page_flip(struct wlr_drm_connector *conn,
 	conn->pending_page_flip = page_flip;
 }
 
+static void page_flip_destroy(struct wlr_drm_page_flip *page_flip) {
+	if (!page_flip) {
+		return;
+	}
+
+	wl_list_remove(&page_flip->link);
+	free(page_flip);
+}
+
 static bool drm_crtc_commit(struct wlr_drm_connector *conn,
 		const struct wlr_drm_connector_state *state,
 		uint32_t flags, bool test_only) {
@@ -433,6 +442,7 @@ static bool drm_crtc_commit(struct wlr_drm_connector *conn,
 			return false;
 		}
 		page_flip->conn = conn;
+		wl_list_insert(&conn->backend->page_flips, &page_flip->link);
 	}
 
 	struct wlr_drm_backend *drm = conn->backend;
@@ -466,7 +476,7 @@ static bool drm_crtc_commit(struct wlr_drm_connector *conn,
 			drm_fb_clear(&layer->pending_fb);
 		}
 
-		free(page_flip);
+		page_flip_destroy(page_flip);
 	}
 	return ok;
 }
@@ -1686,7 +1696,7 @@ static void handle_page_flip(int fd, unsigned seq,
 	if (conn != NULL) {
 		conn->pending_page_flip = NULL;
 	}
-	free(page_flip);
+	page_flip_destroy(page_flip);
 
 	if (conn == NULL) {
 		return;
diff --git a/include/backend/drm/drm.h b/include/backend/drm/drm.h
index b121b3bc..eef778df 100644
--- a/include/backend/drm/drm.h
+++ b/include/backend/drm/drm.h
@@ -104,6 +104,8 @@ struct wlr_drm_backend {
 	struct wl_list fbs; // wlr_drm_fb.link
 	struct wl_list connectors; // wlr_drm_connector.link
 
+	struct wl_list page_flips; // wlr_drm_page_flip.link
+
 	/* Only initialized on multi-GPU setups */
 	struct wlr_drm_renderer mgpu_renderer;
 
@@ -142,6 +144,7 @@ struct wlr_drm_connector_state {
  * that it's been superseded.
  */
 struct wlr_drm_page_flip {
+	struct wl_list link; // wlr_drm_connector.page_flips
 	struct wlr_drm_connector *conn;
 };