From ec14a00e8c6751d0b73ca0ad5f756e4165092b87 Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Sat, 26 Oct 2019 14:00:37 +0200
Subject: [PATCH] Fix segfault in wlr_output_manager_v1_set_configuration

Calling wlr_output_manager_v1_set_configuration with an enabled output
and a NULL mode is incorrect if the output doesn't support modes.

When DPMS'ing an output, wlr_output_enable(output, false) is called.
This de-allocates the CRTC and sets wlr_output.current_mode to NULL.

Because we mark DPMS'ed outputs as enabled, we also need to provide a
correct output mode. Add a field to sway_output to hold the current
mode.

Closes: https://github.com/swaywm/wlroots/issues/1867
---
 include/sway/output.h | 2 ++
 sway/config/output.c  | 1 +
 sway/desktop/output.c | 1 +
 sway/tree/output.c    | 1 +
 4 files changed, 5 insertions(+)

diff --git a/include/sway/output.h b/include/sway/output.h
index c52b30944..7d7057e10 100644
--- a/include/sway/output.h
+++ b/include/sway/output.h
@@ -32,6 +32,8 @@ struct sway_output {
 	int lx, ly; // layout coords
 	int width, height; // transformed buffer size
 	enum wl_output_subpixel detected_subpixel;
+	// last applied mode when the output is DPMS'ed
+	struct wlr_output_mode *current_mode;
 
 	bool enabled, configured;
 	list_t *workspaces;
diff --git a/sway/config/output.c b/sway/config/output.c
index 3c36692f3..50bf1155f 100644
--- a/sway/config/output.c
+++ b/sway/config/output.c
@@ -278,6 +278,7 @@ bool apply_output_config(struct output_config *oc, struct sway_output *output) {
 		sway_log(SWAY_ERROR, "Failed to modeset output %s", wlr_output->name);
 		return false;
 	}
+	output->current_mode = wlr_output->current_mode;
 
 	if (oc && oc->scale > 0) {
 		sway_log(SWAY_DEBUG, "Set %s scale to %f", oc->name, oc->scale);
diff --git a/sway/desktop/output.c b/sway/desktop/output.c
index 42194d540..beb6ee79f 100644
--- a/sway/desktop/output.c
+++ b/sway/desktop/output.c
@@ -662,6 +662,7 @@ static void update_output_manager_config(struct sway_server *server) {
 			root->output_layout, output->wlr_output);
 		// We mark the output enabled even if it is switched off by DPMS
 		config_head->state.enabled = output->enabled;
+		config_head->state.mode = output->current_mode;
 		if (output_box) {
 			config_head->state.x = output_box->x;
 			config_head->state.y = output_box->y;
diff --git a/sway/tree/output.c b/sway/tree/output.c
index 33fdee5ea..07f04ee55 100644
--- a/sway/tree/output.c
+++ b/sway/tree/output.c
@@ -269,6 +269,7 @@ void output_disable(struct sway_output *output) {
 
 	output->enabled = false;
 	output->configured = false;
+	output->current_mode = NULL;
 
 	arrange_root();
 }