output: don't trigger a frame immediately in schedule_frame

This desynchronizes our rendering loop with the vblank cycle.

In case a compositor doesn't swap buffers but schedules a frame,
emitting a frame event immediately enters a busy-loop.

Instead, ask the backend to send a frame when appropriate. On
Wayland we can just register a frame callback on our surface. On
DRM we can do a no-op pageflip.

Fixes #617
Fixes swaywm/sway#2748
This commit is contained in:
emersion 2018-10-05 16:14:22 +02:00
parent 4e89a21397
commit ba91422747
4 changed files with 63 additions and 3 deletions

View File

@ -730,6 +730,43 @@ static bool drm_connector_move_cursor(struct wlr_output *output,
return ok;
}
static void drm_connector_schedule_frame(struct wlr_output *output) {
struct wlr_drm_connector *conn = get_drm_connector_from_output(output);
struct wlr_drm_backend *drm = get_drm_backend_from_backend(output->backend);
if (!drm->session->active) {
return;
}
// We need to figure out where we are in the vblank cycle
// TODO: try using drmWaitVBlank and fallback to pageflipping
struct wlr_drm_crtc *crtc = conn->crtc;
if (!crtc) {
return;
}
struct wlr_drm_plane *plane = crtc->primary;
struct gbm_bo *bo = plane->surf.back;
if (!bo) {
// We haven't swapped buffers yet -- can't do a pageflip
wlr_output_send_frame(output);
return;
}
uint32_t fb_id = get_fb_for_bo(bo);
if (conn->pageflip_pending) {
wlr_log(WLR_ERROR, "Skipping pageflip on output '%s'",
conn->output.name);
return;
}
if (!drm->iface->crtc_pageflip(drm, conn, crtc, fb_id, NULL)) {
return;
}
conn->pageflip_pending = true;
wlr_output_update_enabled(output, true);
}
static void drm_connector_destroy(struct wlr_output *output) {
struct wlr_drm_connector *conn = get_drm_connector_from_output(output);
drm_connector_cleanup(conn);
@ -751,6 +788,7 @@ static const struct wlr_output_impl output_impl = {
.set_gamma = set_drm_connector_gamma,
.get_gamma_size = drm_connector_get_gamma_size,
.export_dmabuf = drm_connector_export_dmabuf,
.schedule_frame = drm_connector_schedule_frame,
};
bool wlr_output_is_drm(struct wlr_output *output) {

View File

@ -192,11 +192,24 @@ void update_wl_output_cursor(struct wlr_wl_output *output) {
}
}
bool output_move_cursor(struct wlr_output *_output, int x, int y) {
static bool output_move_cursor(struct wlr_output *_output, int x, int y) {
// TODO: only return true if x == current x and y == current y
return true;
}
static void output_schedule_frame(struct wlr_output *wlr_output) {
struct wlr_wl_output *output = get_wl_output_from_output(wlr_output);
if (output->frame_callback != NULL) {
wlr_log(WLR_ERROR, "Skipping frame scheduling");
return;
}
output->frame_callback = wl_surface_frame(output->surface);
wl_callback_add_listener(output->frame_callback, &frame_listener, output);
wl_surface_commit(output->surface);
}
static const struct wlr_output_impl output_impl = {
.set_custom_mode = output_set_custom_mode,
.transform = output_transform,
@ -205,6 +218,7 @@ static const struct wlr_output_impl output_impl = {
.swap_buffers = output_swap_buffers,
.set_cursor = output_set_cursor,
.move_cursor = output_move_cursor,
.schedule_frame = output_schedule_frame,
};
bool wlr_output_is_wl(struct wlr_output *wlr_output) {

View File

@ -33,6 +33,7 @@ struct wlr_output_impl {
size_t (*get_gamma_size)(struct wlr_output *output);
bool (*export_dmabuf)(struct wlr_output *output,
struct wlr_dmabuf_attributes *attribs);
void (*schedule_frame)(struct wlr_output *output);
};
void wlr_output_init(struct wlr_output *output, struct wlr_backend *backend,

View File

@ -546,7 +546,13 @@ static void schedule_frame_handle_idle_timer(void *data) {
struct wlr_output *output = data;
output->idle_frame = NULL;
if (!output->frame_pending) {
wlr_output_send_frame(output);
if (output->impl->schedule_frame) {
// Ask the backend to send a frame event when appropriate
output->frame_pending = true;
output->impl->schedule_frame(output);
} else {
wlr_output_send_frame(output);
}
}
}
@ -555,7 +561,8 @@ void wlr_output_schedule_frame(struct wlr_output *output) {
return;
}
// TODO: ask the backend to send a frame event when appropriate instead
// We're using an idle timer here in case a buffer swap happens right after
// this function is called
struct wl_event_loop *ev = wl_display_get_event_loop(output->display);
output->idle_frame =
wl_event_loop_add_idle(ev, schedule_frame_handle_idle_timer, output);