From ba9142274765869cd58ec0c55e7ef8da0354ed25 Mon Sep 17 00:00:00 2001 From: emersion Date: Fri, 5 Oct 2018 16:14:22 +0200 Subject: 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 --- backend/drm/drm.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'backend/drm') diff --git a/backend/drm/drm.c b/backend/drm/drm.c index 0187e5d0..b9ab7f82 100644 --- a/backend/drm/drm.c +++ b/backend/drm/drm.c @@ -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) { -- cgit v1.2.3