Working commit

backend/drm/backend.c

@@ -37,6 +37,29 @@ static struct wlr_backend_impl backend_impl = {
 	.destroy = wlr_drm_backend_destroy
 };
 
+static void device_paused(struct wl_listener *listener, void *data) {
+	struct wlr_backend_state *backend = wl_container_of(listener, backend, device_paused);
+
+	// TODO: Actually pause the renderer or something.
+	// We currently just expect it to fail its next pageflip.
+
+	(void)backend;
+}
+
+static void device_resumed(struct wl_listener *listener, void *data) {
+	struct wlr_backend_state *drm = wl_container_of(listener, drm, device_paused);
+	int *new_fd = data;
+
+	close(drm->fd);
+	drm->fd = *new_fd;
+	drm->renderer.fd = *new_fd;
+
+	for (size_t i = 0; i < drm->outputs->length; ++i) {
+		struct wlr_output_state *output = drm->outputs->items[i];
+		wlr_drm_output_draw_blank(output);
+	}
+}
+
 struct wlr_backend *wlr_drm_backend_create(struct wl_display *display,
 		struct wlr_session *session) {
 	struct wlr_backend_state *state = calloc(1, sizeof(struct wlr_backend_state));
@@ -79,6 +102,15 @@ struct wlr_backend *wlr_drm_backend_create(struct wl_display *display,
 		goto error_fd;
 	}
 
+	wl_list_init(&state->device_paused.link);
+	wl_list_init(&state->device_paused.link);
+
+	state->device_paused.notify = device_paused;
+	state->device_resumed.notify = device_resumed;
+
+	wl_signal_add(&session->device_paused, &state->device_paused);
+	wl_signal_add(&session->device_resumed, &state->device_resumed);
+
 	// TODO: what is the difference between the per-output renderer and this
 	// one?
 	if (!wlr_drm_renderer_init(&state->renderer, state->fd)) {

backend/drm/drm.c

@@ -474,3 +474,31 @@ void wlr_drm_output_dpms(int fd, struct wlr_output_state *output, bool screen_on
 			DRM_MODE_DPMS_STANDBY);
 	}
 }
+
+void wlr_drm_output_draw_blank(struct wlr_output_state *output) {
+	if (output->state != DRM_OUTPUT_CONNECTED) {
+		return;
+	}
+
+	struct wlr_drm_renderer *renderer = output->renderer;
+
+	eglMakeCurrent(renderer->egl.display, output->egl, output->egl, renderer->egl.context);
+
+	glViewport(0, 0, output->width, output->height);
+	glClearColor(0.0, 0.0, 0.0, 1.0);
+	glClear(GL_COLOR_BUFFER_BIT);
+
+	eglSwapBuffers(renderer->egl.display, output->egl);
+
+	struct gbm_bo *bo = gbm_surface_lock_front_buffer(output->gbm);
+	uint32_t fb_id = get_fb_for_bo(renderer->fd, bo);
+
+	drmModeSetCrtc(renderer->fd, output->crtc, fb_id, 0, 0,
+			&output->connector, 1, &output->wlr_output->current_mode->state->mode);
+	drmModePageFlip(renderer->fd, output->crtc, fb_id,
+			DRM_MODE_PAGE_FLIP_EVENT, output);
+
+	gbm_surface_release_buffer(output->gbm, bo);
+
+	wlr_log(L_INFO, "Drew blank frame");
+}

example/main.c

@@ -129,7 +129,7 @@ int main() {
 	struct wl_event_source *timer_vt = wl_event_loop_add_timer(event_loop,
 		timer_change_vt, session);
 
-	wl_event_source_timer_update(timer, 30000);
+	wl_event_source_timer_update(timer, 15000);
 	wl_event_source_timer_update(timer_vt, 5000);
 
 	while (!done) {

include/backend/drm/backend.h

@@ -23,6 +23,9 @@ struct wlr_backend_state {
 	struct wlr_backend *backend;
 	struct wl_event_source *drm_event;
 
+	struct wl_listener device_paused;
+	struct wl_listener device_resumed;
+
 	uint32_t taken_crtcs;
 	list_t *outputs;
 

include/backend/drm/drm.h

@@ -60,4 +60,6 @@ void wlr_drm_output_dpms(int fd, struct wlr_output_state *output, bool screen_on
 void wlr_drm_scan_connectors(struct wlr_backend_state *state);
 int wlr_drm_event(int fd, uint32_t mask, void *data);
 
+void wlr_drm_output_draw_blank(struct wlr_output_state *output);
+
 #endif

include/session/interface.h

@@ -1,7 +1,7 @@
 #ifndef WLR_SESSION_INTERFACE_H
 #define WLR_SESSION_INTERFACE_H
 
-struct wlr_session;
+#include <wlr/session.h>
 
 struct session_interface {
 	struct wlr_session *(*start)(struct wl_display *disp);
@@ -12,10 +12,6 @@ struct session_interface {
 	bool (*change_vt)(struct wlr_session *session, int vt);
 };
 
-struct wlr_session {
-	struct session_interface iface;
-};
-
 extern const struct session_interface session_logind_iface;
 extern const struct session_interface session_direct_iface;
 

include/wlr/session.h

@@ -3,7 +3,14 @@
 
 #include <wayland-server.h>
 
-struct wlr_session;
+struct session_interface;
+
+struct wlr_session {
+	const struct session_interface *iface;
+
+	struct wl_signal device_paused;
+	struct wl_signal device_resumed;
+};
 
 struct wlr_session *wlr_session_start(struct wl_display *disp);
 void wlr_session_finish(struct wlr_session *session);

session/direct.c

@@ -44,7 +44,9 @@ static struct wlr_session *direct_session_start(struct wl_display *disp) {
 
 	wlr_log(L_INFO, "Successfully loaded direct session");
 
-	session->base.iface = session_direct_iface;
+	session->base.iface = &session_direct_iface;
+	wl_signal_init(&session->base.device_paused);
+	wl_signal_init(&session->base.device_resumed);
 	return &session->base;
 }
 

session/logind.c

@@ -187,11 +187,59 @@ static int session_removed(sd_bus_message *msg, void *userdata, sd_bus_error *re
 
 static int pause_device(sd_bus_message *msg, void *userdata, sd_bus_error *ret_error) {
 	wlr_log(L_INFO, "PauseDevice signal received");
+	struct logind_session *session = userdata;
+	int ret;
+
+	uint32_t major, minor;
+	ret = sd_bus_message_read(msg, "uu", &major, &minor);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to parse D-Bus response for PauseDevice: %s",
+			strerror(-ret));
+		goto error;
+	}
+
+	dev_t dev = makedev(major, minor);
+	wl_signal_emit(&session->base.device_paused, &dev);
+
+	ret = sd_bus_call_method(session->bus, "org.freedesktop.login1",
+		session->path, "org.freedesktop.login1.Session", "PauseDeviceComplete",
+		ret_error, &msg, "uu", major, minor);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to send PauseDeviceComplete signal");
+	}
+
+error:
 	return 0;
 }
 
 static int resume_device(sd_bus_message *msg, void *userdata, sd_bus_error *ret_error) {
 	wlr_log(L_INFO, "ResumeDevice signal received");
+	struct logind_session *session = userdata;
+	int ret;
+
+	int fd;
+	uint32_t major, minor;
+	ret = sd_bus_message_read(msg, "uuh", &major, &minor, &fd);
+	if (ret < 0) {
+		wlr_log(L_ERROR, "Failed to parse D-Bus response for ResumeDevice: %s",
+			strerror(-ret));
+		goto error;
+	}
+
+	// The original fd seem to be closed when the message is freed
+	// so we just clone it.
+	fd = fcntl(fd, F_DUPFD_CLOEXEC, 0);
+	if (fd == -1) {
+		wlr_log(L_ERROR, "Failed to clone file descriptor for ResumeDevice: %s",
+			strerror(errno));
+		goto error;
+	}
+
+	// TODO: Use major/minor to make sure the right devices are getting signals
+
+	wl_signal_emit(&session->base.device_resumed, &fd);
+
+error:
 	return 0;
 }
 
@@ -289,7 +337,9 @@ static struct wlr_session *logind_session_start(struct wl_display *disp) {
 
 	wlr_log(L_INFO, "Successfully loaded logind session");
 
-	session->base.iface = session_logind_iface;
+	session->base.iface = &session_logind_iface;
+	wl_signal_init(&session->base.device_paused);
+	wl_signal_init(&session->base.device_resumed);
 	return &session->base;
 
 error_bus:

session/session.c

@@ -28,19 +28,19 @@ struct wlr_session *wlr_session_start(struct wl_display *disp) {
 }
 
 void wlr_session_finish(struct wlr_session *session) {
-	session->iface.finish(session);
+	session->iface->finish(session);
 };
 
 int wlr_session_open_file(struct wlr_session *restrict session,
 	const char *restrict path) {
 
-	return session->iface.open(session, path);
+	return session->iface->open(session, path);
 }
 
 void wlr_session_close_file(struct wlr_session *session, int fd) {
-	session->iface.close(session, fd);
+	session->iface->close(session, fd);
 }
 
 bool wlr_session_change_vt(struct wlr_session *session, int vt) {
-	return session->iface.change_vt(session, vt);
+	return session->iface->change_vt(session, vt);
 }