output: Remove output_ensure_buffer

Compositors are now required to commit a buffer themselves when they
modeset.

include/types/wlr_output.h

@@ -12,8 +12,6 @@ bool output_pending_enabled(struct wlr_output *output,
 bool output_pick_format(struct wlr_output *output,
 	const struct wlr_drm_format_set *display_formats,
 	struct wlr_drm_format *format, uint32_t fmt);
-bool output_ensure_buffer(struct wlr_output *output,
-	struct wlr_output_state *state, bool *new_back_buffer);
 
 bool output_cursor_set_texture(struct wlr_output_cursor *cursor,
 	struct wlr_texture *texture, bool own_texture, const struct wlr_fbox *src_box,

types/output/output.c

@@ -721,16 +721,7 @@ bool wlr_output_test_state(struct wlr_output *output,
 		return true;
 	}
 
-	bool new_back_buffer = false;
+	return output->impl->test(output, &copy);
-	if (!output_ensure_buffer(output, &copy, &new_back_buffer)) {
-		return false;
-	}
-
-	bool success = output->impl->test(output, &copy);
-	if (new_back_buffer) {
-		wlr_buffer_unlock(copy.buffer);
-	}
-	return success;
 }
 
 bool output_prepare_commit(struct wlr_output *output, const struct wlr_output_state *state) {
@@ -792,28 +783,16 @@ bool wlr_output_commit_state(struct wlr_output *output,
 		return false;
 	}
 
-	bool new_back_buffer = false;
-	if (!output_ensure_buffer(output, &pending, &new_back_buffer)) {
-		return false;
-	}
-
 	if (!output_prepare_commit(output, &pending)) {
 		return false;
 	}
 
 	if (!output->impl->commit(output, &pending)) {
-		if (new_back_buffer) {
-			wlr_buffer_unlock(pending.buffer);
-		}
 		return false;
 	}
 
 	output_apply_commit(output, &pending);
 
-	if (new_back_buffer) {
-		wlr_buffer_unlock(pending.buffer);
-	}
-
 	return true;
 }
 

types/output/render.c

@@ -38,100 +38,6 @@ bool wlr_output_init_render(struct wlr_output *output,
 	return true;
 }
 
-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));
-
-	// wlr_output_configure_primary_swapchain() function will call
-	// wlr_output_test_state(), which can call us again. This is dangerous: we
-	// risk infinite recursion. However, a buffer will always be supplied in
-	// wlr_output_test_state(), which will prevent us from being called.
-	if (!wlr_output_configure_primary_swapchain(output, state,
-			&output->swapchain)) {
-		return NULL;
-	}
-
-	struct wlr_buffer *buffer = wlr_swapchain_acquire(output->swapchain);
-	if (buffer == NULL) {
-		return NULL;
-	}
-
-	struct wlr_render_pass *pass =
-		wlr_renderer_begin_buffer_pass(output->renderer, buffer, NULL);
-	if (pass == NULL) {
-		wlr_buffer_unlock(buffer);
-		return NULL;
-	}
-
-	wlr_render_pass_add_rect(pass, &(struct wlr_render_rect_options){
-		.color = { 0, 0, 0, 0 },
-		.blend_mode = WLR_RENDER_BLEND_MODE_NONE,
-	});
-
-	if (!wlr_render_pass_submit(pass)) {
-		wlr_buffer_unlock(buffer);
-		return NULL;
-	}
-
-	return buffer;
-}
-
-// This function may attach a new, empty buffer if necessary.
-// If so, the new_back_buffer out parameter will be set to true.
-bool output_ensure_buffer(struct wlr_output *output,
-		struct wlr_output_state *state, bool *new_buffer) {
-	assert(*new_buffer == false);
-
-	// If we already have a buffer, we don't need to allocate a new one
-	if (state->committed & WLR_OUTPUT_STATE_BUFFER) {
-		return true;
-	}
-
-	// If the compositor hasn't called wlr_output_init_render(), they will use
-	// their own logic to attach buffers
-	if (output->renderer == NULL) {
-		return true;
-	}
-
-	bool enabled = output->enabled;
-	if (state->committed & WLR_OUTPUT_STATE_ENABLED) {
-		enabled = state->enabled;
-	}
-
-	// If we're lighting up an output or changing its mode, make sure to
-	// provide a new buffer
-	bool needs_new_buffer = false;
-	if ((state->committed & WLR_OUTPUT_STATE_ENABLED) && state->enabled) {
-		needs_new_buffer = true;
-	}
-	if (state->committed & WLR_OUTPUT_STATE_MODE) {
-		needs_new_buffer = true;
-	}
-	if (state->committed & WLR_OUTPUT_STATE_RENDER_FORMAT) {
-		needs_new_buffer = true;
-	}
-	if (state->allow_reconfiguration && output->commit_seq == 0 && enabled) {
-		// On first commit, require a new buffer if the compositor called a
-		// mode-setting function, even if the mode won't change. This makes it
-		// so the swapchain is created now.
-		needs_new_buffer = true;
-	}
-	if (!needs_new_buffer) {
-		return true;
-	}
-
-	wlr_log(WLR_DEBUG, "Attaching empty buffer to output for modeset");
-	struct wlr_buffer *buffer = output_acquire_empty_buffer(output, state);
-	if (buffer == NULL) {
-		return false;
-	}
-
-	*new_buffer = true;
-	wlr_output_state_set_buffer(state, buffer);
-	wlr_buffer_unlock(buffer);
-	return true;
-}
-
 void wlr_output_lock_attach_render(struct wlr_output *output, bool lock) {
 	if (lock) {
 		++output->attach_render_locks;