Merge pull request #1272 from emersion/presentation-time

Implement presentation-time

2 files changed, 34 insertions, 5 deletions

diff --git a/backend/drm/backend.c b/backend/drm/backend.c
index b298365e..a9082077 100644
--- a/backend/drm/backend.c
+++ b/backend/drm/backend.c
@@ -65,10 +65,16 @@ static struct wlr_renderer *backend_get_renderer(
 	}
 }
 
+static clockid_t backend_get_presentation_clock(struct wlr_backend *backend) {
+	struct wlr_drm_backend *drm = get_drm_backend_from_backend(backend);
+	return drm->clock;
+}
+
 static struct wlr_backend_impl backend_impl = {
 	.start = backend_start,
 	.destroy = backend_destroy,
 	.get_renderer = backend_get_renderer,
+	.get_presentation_clock = backend_get_presentation_clock,
 };
 
 bool wlr_backend_is_drm(struct wlr_backend *b) {
diff --git a/backend/drm/drm.c b/backend/drm/drm.c
index fa9a95ae..0187e5d0 100644
--- a/backend/drm/drm.c
+++ b/backend/drm/drm.c
@@ -1,3 +1,4 @@
+#define _POSIX_C_SOURCE 199309L
 #include <assert.h>
 #include <drm_mode.h>
 #include <EGL/egl.h>
@@ -27,8 +28,8 @@
 #include "util/signal.h"
 
 bool check_drm_features(struct wlr_drm_backend *drm) {
+	uint64_t cap;
 	if (drm->parent) {
-		uint64_t cap;
 		if (drmGetCap(drm->fd, DRM_CAP_PRIME, &cap) ||
 				!(cap & DRM_PRIME_CAP_IMPORT)) {
 			wlr_log(WLR_ERROR,
@@ -51,16 +52,21 @@ bool check_drm_features(struct wlr_drm_backend *drm) {
 
 	const char *no_atomic = getenv("WLR_DRM_NO_ATOMIC");
 	if (no_atomic && strcmp(no_atomic, "1") == 0) {
-		wlr_log(WLR_DEBUG, "WLR_DRM_NO_ATOMIC set, forcing legacy DRM interface");
+		wlr_log(WLR_DEBUG,
+			"WLR_DRM_NO_ATOMIC set, forcing legacy DRM interface");
 		drm->iface = &legacy_iface;
 	} else if (drmSetClientCap(drm->fd, DRM_CLIENT_CAP_ATOMIC, 1)) {
-		wlr_log(WLR_DEBUG, "Atomic modesetting unsupported, using legacy DRM interface");
+		wlr_log(WLR_DEBUG,
+			"Atomic modesetting unsupported, using legacy DRM interface");
 		drm->iface = &legacy_iface;
 	} else {
 		wlr_log(WLR_DEBUG, "Using atomic DRM interface");
 		drm->iface = &atomic_iface;
 	}
 
+	int ret = drmGetCap(drm->fd, DRM_CAP_TIMESTAMP_MONOTONIC, &cap);
+	drm->clock = (ret == 0 && cap == 1) ? CLOCK_MONOTONIC : CLOCK_REALTIME;
+
 	return true;
 }
 
@@ -1148,9 +1154,13 @@ void scan_drm_connectors(struct wlr_drm_backend *drm) {
 	attempt_enable_needs_modeset(drm);
 }
 
+static int mhz_to_nsec(int mhz) {
+	return 1000000000000LL / mhz;
+}
+
 static void page_flip_handler(int fd, unsigned seq,
-		unsigned tv_sec, unsigned tv_usec, void *user) {
-	struct wlr_drm_connector *conn = user;
+		unsigned tv_sec, unsigned tv_usec, void *data) {
+	struct wlr_drm_connector *conn = data;
 	struct wlr_drm_backend *drm =
 		get_drm_backend_from_backend(conn->output.backend);
 
@@ -1170,6 +1180,19 @@ static void page_flip_handler(int fd, unsigned seq,
 		post_drm_surface(&conn->crtc->primary->mgpu_surf);
 	}
 
+	struct timespec present_time = {
+		.tv_sec = tv_sec,
+		.tv_nsec = tv_usec * 1000,
+	};
+	struct wlr_output_event_present present_event = {
+		.when = &present_time,
+		.seq = seq,
+		.refresh = mhz_to_nsec(conn->output.refresh),
+		.flags = WLR_OUTPUT_PRESENT_VSYNC | WLR_OUTPUT_PRESENT_HW_CLOCK |
+			WLR_OUTPUT_PRESENT_HW_COMPLETION,
+	};
+	wlr_output_send_present(&conn->output, &present_event);
+
 	if (drm->session->active) {
 		wlr_output_send_frame(&conn->output);
 	}