From b909cc71cdc853a67bfb9323290b4ddc165cba72 Mon Sep 17 00:00:00 2001
From: Kirill Primak <vyivel@eclair.cafe>
Date: Sun, 26 Nov 2023 00:51:50 +0300
Subject: [PATCH] backend/x11: don't send ConfigureRequest with the same size

Under X11, ConfigureNotify means that the window has already been resized.
Sending ConfigureRequest with the received size is not only useless, but also
can confuse the window manager, which will probably reply with the current
(i.e. *old*) size causing a configure loop.

Fixes: https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3769
(cherry picked from commit 4990ed99ebc8eeb508e0077f620ec2df781fabdb)
---
 backend/x11/output.c  | 13 +++++++++++++
 include/backend/x11.h |  2 ++
 2 files changed, 15 insertions(+)

diff --git a/backend/x11/output.c b/backend/x11/output.c
index f5dc527c2..59f2d87d8 100644
--- a/backend/x11/output.c
+++ b/backend/x11/output.c
@@ -64,6 +64,10 @@ static bool output_set_custom_mode(struct wlr_output *wlr_output,
 	struct wlr_x11_output *output = get_x11_output_from_output(wlr_output);
 	struct wlr_x11_backend *x11 = output->x11;
 
+	if (width == output->win_width && height == output->win_height) {
+		return true;
+	}
+
 	const uint32_t values[] = { width, height };
 	xcb_void_cookie_t cookie = xcb_configure_window_checked(
 		x11->xcb, output->win,
@@ -77,6 +81,9 @@ static bool output_set_custom_mode(struct wlr_output *wlr_output,
 		return false;
 	}
 
+	output->win_width = width;
+	output->win_height = height;
+
 	// Move the pointer to its new location
 	update_x11_pointer_position(output, output->x11->time);
 
@@ -579,6 +586,9 @@ struct wlr_output *wlr_x11_output_create(struct wlr_backend *backend) {
 		x11->screen->root, 0, 0, wlr_output->width, wlr_output->height, 0,
 		XCB_WINDOW_CLASS_INPUT_OUTPUT, x11->visualid, mask, values);
 
+	output->win_width = wlr_output->width;
+	output->win_height = wlr_output->height;
+
 	struct {
 		xcb_input_event_mask_t head;
 		xcb_input_xi_event_mask_t mask;
@@ -640,6 +650,9 @@ void handle_x11_configure_notify(struct wlr_x11_output *output,
 		return;
 	}
 
+	output->win_width = ev->width;
+	output->win_height = ev->height;
+
 	struct wlr_output_state state;
 	wlr_output_state_init(&state);
 	wlr_output_state_set_custom_mode(&state, ev->width, ev->height, 0);
diff --git a/include/backend/x11.h b/include/backend/x11.h
index 06834c1cb..9eb208b15 100644
--- a/include/backend/x11.h
+++ b/include/backend/x11.h
@@ -35,6 +35,8 @@ struct wlr_x11_output {
 	xcb_window_t win;
 	xcb_present_event_t present_event_id;
 
+	int32_t win_width, win_height;
+
 	struct wlr_pointer pointer;
 
 	struct wlr_touch touch;