set refresh rate in config.h

config.def.h

@@ -28,12 +28,12 @@ static const Layout layouts[] = {
  * The order in which monitors are defined determines their position.
  * Non-configured monitors are always added to the left. */
 static const MonitorRule monrules[] = {
-	/* name       mfact nmaster scale layout       rotate/reflect x y */
+	/* name       mfact nmaster scale layout       rotate/reflect x y resx resy rate      custom*/
-	/* example of a HiDPI laptop monitor:
+	/* example of a HiDPI laptop monitor at 120Hz:
-	{ "eDP-1",    0.5,  1,      2,    &layouts[0], WL_OUTPUT_TRANSFORM_NORMAL, 0, 0 },
+	{ "eDP-1",    0.5,  1,      2,    &layouts[0], WL_OUTPUT_TRANSFORM_NORMAL, 0, 0, 0, 0, 120.000 , 0},
 	*/
 	/* defaults */
-	{ NULL,       0.55, 1,      1,    &layouts[0], WL_OUTPUT_TRANSFORM_NORMAL, 0, 0 },
+	{ NULL,       0.55, 1,      1,    &layouts[0], WL_OUTPUT_TRANSFORM_NORMAL, 0, 0, 0, 0, 0, 0},
 };
 
 /* keyboard */

dwl.c

@@ -189,6 +189,10 @@ typedef struct {
 	enum wl_output_transform rr;
 	int x;
 	int y;
+	int resx;
+	int resy;
+	int rate;
+	bool custom_mode;
 } MonitorRule;
 
 typedef struct {
@@ -809,13 +813,47 @@ createkeyboard(struct wlr_input_device *device)
 	/* And add the keyboard to our list of keyboards */
 	wl_list_insert(&keyboards, &kb->link);
 }
+void
+set_mode(struct wlr_output *output, int width, int height,
+		float refresh_rate, bool custom) {
+	// Not all floating point integers can be represented exactly
+	// as (int)(1000 * mHz / 1000.f)
+	// round() the result to avoid any error
+	int mhz = (int)round(refresh_rate * 1000);
 
+	if (wl_list_empty(&output->modes) || custom) {
+		wlr_output_set_custom_mode(output, width, height,
+			refresh_rate > 0 ? mhz : 0);
+		return;
+	}
+
+	struct wlr_output_mode *mode, *best = NULL;
+	wl_list_for_each(mode, &output->modes, link) {
+		if (mode->width == width && mode->height == height) {
+			if (mode->refresh == mhz) {
+				best = mode;
+				break;
+			}
+			if (best == NULL || mode->refresh > best->refresh) {
+				best = mode;
+			}
+		}
+	}
+	if (!best) {
+		best = wlr_output_preferred_mode(output);
+	} else {
+	}
+	wlr_output_set_mode(output, best);
+}
 void
 createmon(struct wl_listener *listener, void *data)
 {
 	/* This event is raised by the backend when a new output (aka a display or
 	 * monitor) becomes available. */
 	struct wlr_output *wlr_output = data;
+	const struct wlr_output_mode *wlr_output_mode;
+	int32_t resx,resy,rate;
+	bool custom_mode;
 	const MonitorRule *r;
 	Monitor *m = wlr_output->data = calloc(1, sizeof(*m));
 	m->wlr_output = wlr_output;
@@ -824,6 +862,13 @@ createmon(struct wl_listener *listener, void *data)
 	for (size_t i = 0; i < LENGTH(m->layers); i++)
 		wl_list_init(&m->layers[i]);
 	m->tagset[0] = m->tagset[1] = 1;
+	
+	/* The mode is a tuple of (width, height, refresh rate), and each
+	 * monitor supports only a specific set of modes. Default to the
+	 * preferred mode, which will be overwritten if the user
+	 * specifies a different one*/
+	wlr_output_set_mode(wlr_output, wlr_output_preferred_mode(wlr_output));
+
 	for (r = monrules; r < END(monrules); r++) {
 		if (!r->name || strstr(wlr_output->name, r->name)) {
 			m->mfact = r->mfact;
@@ -832,15 +877,28 @@ createmon(struct wl_listener *listener, void *data)
 			wlr_xcursor_manager_load(cursor_mgr, r->scale);
 			m->lt[0] = m->lt[1] = r->lt;
 			wlr_output_set_transform(wlr_output, r->rr);
+
+			wlr_output_mode = wlr_output_preferred_mode(wlr_output);
+
+			if (r->rate)
+				rate = r->rate;
+			else
+				rate = wlr_output_mode->refresh;
+			if (r->resx)
+				resx = r->resx;
+			else
+				resx = wlr_output_mode->width;
+			if (r->resy)
+				resy = r->resy;
+			else
+				resy = wlr_output_mode->height;
+
+			set_mode(wlr_output, resx, resy, rate, custom_mode);
+
 			break;
 		}
 	}
 
-	/* The mode is a tuple of (width, height, refresh rate), and each
-	 * monitor supports only a specific set of modes. We just pick the
-	 * monitor's preferred mode; a more sophisticated compositor would let
-	 * the user configure it. */
-	wlr_output_set_mode(wlr_output, wlr_output_preferred_mode(wlr_output));
 	wlr_output_enable_adaptive_sync(wlr_output, 1);
 
 	/* Set up event listeners */