output: Drop back_buffer

include/wlr/types/wlr_output.h

@@ -200,7 +200,6 @@ struct wlr_output {
 	struct wlr_allocator *allocator;
 	struct wlr_renderer *renderer;
 	struct wlr_swapchain *swapchain;
-	struct wlr_buffer *back_buffer;
 
 	struct wl_listener display_destroy;
 

types/output/output.c

@@ -440,7 +440,6 @@ void wlr_output_destroy(struct wlr_output *output) {
 	}
 
 	wlr_output_destroy_global(output);
-	output_clear_back_buffer(output);
 
 	wl_list_remove(&output->display_destroy.link);
 
@@ -761,12 +760,6 @@ bool wlr_output_test_state(struct wlr_output *output,
 bool wlr_output_test(struct wlr_output *output) {
 	struct wlr_output_state state = output->pending;
 
-	if (output->back_buffer != NULL) {
-		assert((state.committed & WLR_OUTPUT_STATE_BUFFER) == 0);
-		state.committed |= WLR_OUTPUT_STATE_BUFFER;
-		state.buffer = output->back_buffer;
-	}
-
 	return wlr_output_test_state(output, &state);
 }
 
@@ -840,22 +833,12 @@ bool wlr_output_commit(struct wlr_output *output) {
 	struct wlr_output_state state = {0};
 	output_state_move(&state, &output->pending);
 
-	// output_clear_back_buffer detaches the buffer from the renderer. This is
-	// important to do before calling impl->commit(), because this marks an
-	// implicit rendering synchronization point. The backend needs it to avoid
-	// displaying a buffer when asynchronous GPU work isn't finished.
-	if (output->back_buffer != NULL) {
-		wlr_output_state_set_buffer(&state, output->back_buffer);
-		output_clear_back_buffer(output);
-	}
-
 	bool ok = wlr_output_commit_state(output, &state);
 	wlr_output_state_finish(&state);
 	return ok;
 }
 
 void wlr_output_rollback(struct wlr_output *output) {
-	output_clear_back_buffer(output);
 	output_state_clear(&output->pending);
 }
 

types/output/render.c

@@ -16,7 +16,6 @@
 bool wlr_output_init_render(struct wlr_output *output,
 		struct wlr_allocator *allocator, struct wlr_renderer *renderer) {
 	assert(allocator != NULL && renderer != NULL);
-	assert(output->back_buffer == NULL);
 
 	uint32_t backend_caps = backend_get_buffer_caps(output->backend);
 	uint32_t renderer_caps = renderer_get_render_buffer_caps(renderer);
@@ -43,20 +42,6 @@ bool wlr_output_init_render(struct wlr_output *output,
 	return true;
 }
 
-void output_clear_back_buffer(struct wlr_output *output) {
-	if (output->back_buffer == NULL) {
-		return;
-	}
-
-	struct wlr_renderer *renderer = output->renderer;
-	assert(renderer != NULL);
-
-	renderer_bind_buffer(renderer, NULL);
-
-	wlr_buffer_unlock(output->back_buffer);
-	output->back_buffer = NULL;
-}
-
 static struct wlr_buffer *output_acquire_empty_buffer(struct wlr_output *output,
 		const struct wlr_output_state *state) {
 	assert(!(state->committed & WLR_OUTPUT_STATE_BUFFER));