handle ephemeral pageflip failures

If a transient failure occurs in wlr_output_commit, re-render until it
doesn't happen.  This could possibly be removed if we decide to
implement damage tracking in the future.

1 files changed, 31 insertions, 27 deletions

diff --git a/dwl.c b/dwl.c
index e0b404e..a38f452 100644
--- a/dwl.c
+++ b/dwl.c
@@ -1726,38 +1726,42 @@ rendermon(struct wl_listener *listener, void *data)
 		}
 	}
 
-	/* wlr_output_attach_render makes the OpenGL context current. */
-	if (!wlr_output_attach_render(m->wlr_output, NULL))
-		return;
+	/* HACK: This loop is the simplest way to handle ephemeral pageflip
+	 * failures but probably not the best. Revisit if damage tracking is
+	 * added. */
+	do {
+		/* wlr_output_attach_render makes the OpenGL context current. */
+		if (!wlr_output_attach_render(m->wlr_output, NULL))
+			return;
 
-	if (render) {
-		/* Begin the renderer (calls glViewport and some other GL sanity checks) */
-		wlr_renderer_begin(drw, m->wlr_output->width, m->wlr_output->height);
-		wlr_renderer_clear(drw, rootcolor);
+		if (render) {
+			/* Begin the renderer (calls glViewport and some other GL sanity checks) */
+			wlr_renderer_begin(drw, m->wlr_output->width, m->wlr_output->height);
+			wlr_renderer_clear(drw, rootcolor);
 
-		renderlayer(&m->layers[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND], &now);
-		renderlayer(&m->layers[ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM], &now);
-		renderclients(m, &now);
+			renderlayer(&m->layers[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND], &now);
+			renderlayer(&m->layers[ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM], &now);
+			renderclients(m, &now);
 #ifdef XWAYLAND
-		renderindependents(m->wlr_output, &now);
+			renderindependents(m->wlr_output, &now);
 #endif
-		renderlayer(&m->layers[ZWLR_LAYER_SHELL_V1_LAYER_TOP], &now);
-		renderlayer(&m->layers[ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY], &now);
-
-		/* Hardware cursors are rendered by the GPU on a separate plane, and can be
-		 * moved around without re-rendering what's beneath them - which is more
-		 * efficient. However, not all hardware supports hardware cursors. For this
-		 * reason, wlroots provides a software fallback, which we ask it to render
-		 * here. wlr_cursor handles configuring hardware vs software cursors for you,
-		 * and this function is a no-op when hardware cursors are in use. */
-		wlr_output_render_software_cursors(m->wlr_output, NULL);
-
-		/* Conclude rendering and swap the buffers, showing the final frame
-		 * on-screen. */
-		wlr_renderer_end(drw);
-	}
+			renderlayer(&m->layers[ZWLR_LAYER_SHELL_V1_LAYER_TOP], &now);
+			renderlayer(&m->layers[ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY], &now);
+
+			/* Hardware cursors are rendered by the GPU on a separate plane, and can be
+			 * moved around without re-rendering what's beneath them - which is more
+			 * efficient. However, not all hardware supports hardware cursors. For this
+			 * reason, wlroots provides a software fallback, which we ask it to render
+			 * here. wlr_cursor handles configuring hardware vs software cursors for you,
+			 * and this function is a no-op when hardware cursors are in use. */
+			wlr_output_render_software_cursors(m->wlr_output, NULL);
+
+			/* Conclude rendering and swap the buffers, showing the final frame
+			 * on-screen. */
+			wlr_renderer_end(drw);
+		}
 
-	wlr_output_commit(m->wlr_output);
+	} while (!wlr_output_commit(m->wlr_output));
 }
 
 void