From c7cf87fe85c386488c12150ab6c817b7ff6f7e3c Mon Sep 17 00:00:00 2001
From: Derek Foreman <derek.foreman@collabora.com>
Date: Mon, 3 Feb 2025 12:29:01 -0600
Subject: [PATCH] frontend: Enable VRR from the config file

Allow weston.ini to enable game VRR.

Signed-off-by: Derek Foreman <derek.foreman@collabora.com>
---
 frontend/main.c    | 53 ++++++++++++++++++++++++++++++++++++++++++++++
 man/weston.ini.man | 13 ++++++++++++
 2 files changed, 66 insertions(+)

diff --git a/frontend/main.c b/frontend/main.c
index c27c011d9..c35a16077 100644
--- a/frontend/main.c
+++ b/frontend/main.c
@@ -1361,6 +1361,56 @@ wet_output_set_transform(struct weston_output *output,
 	return 0;
 }
 
+static int
+wet_output_set_vrr_mode(struct weston_output *output,
+			struct weston_config_section *section)
+{
+	static const struct {
+		const char *name;
+		enum weston_vrr_mode vrr_mode;
+	} vrr_modes[] = {
+		{ "none",	WESTON_VRR_MODE_NONE },
+		{ "game", 	WESTON_VRR_MODE_GAME },
+	};
+	enum weston_vrr_mode vrr_mode = WESTON_VRR_MODE_NONE;
+	char *vrr_str = NULL;
+	unsigned int i;
+
+	weston_config_section_get_string(section, "vrr-mode", &vrr_str, NULL);
+	if (!vrr_str)
+		return vrr_mode;
+
+	for (i = 0; i < ARRAY_LENGTH(vrr_modes); i++)
+		if (strcmp(vrr_str, vrr_modes[i].name) == 0)
+			break;
+
+	if (i == ARRAY_LENGTH(vrr_modes)) {
+		weston_log("Error in config for output '%s': '%s' is not a valid vrr mode. Try one of:",
+			   output->name, vrr_str);
+		for (i = 0; i < ARRAY_LENGTH(vrr_modes); i++)
+			weston_log_continue(" %s", vrr_modes[i].name);
+		weston_log_continue("\n");
+		free(vrr_str);
+		return -1;
+	}
+
+	vrr_mode = vrr_modes[i].vrr_mode;
+
+	if (vrr_mode && (weston_output_get_supported_vrr_modes(output) & vrr_mode) == 0) {
+		weston_log("Error: output '%s' does not support output format %s.\n",
+			   output->name, vrr_str);
+		free(vrr_str);
+		return -1;
+	}
+
+	free(vrr_str);
+
+	if (weston_output_set_vrr_mode(output, vrr_mode) < 0)
+		return -1;
+
+	return 0;
+}
+
 static int
 wet_output_set_color_profile(struct weston_output *output,
 			     struct weston_config_section *section,
@@ -2423,6 +2473,9 @@ drm_backend_output_configure(struct weston_output *output,
 						 wet->config, section) < 0)
 		return -1;
 
+	if (wet_output_set_vrr_mode(output, section) < 0)
+		return -1;
+
 	return 0;
 }
 
diff --git a/man/weston.ini.man b/man/weston.ini.man
index a8b501ec3..f079a9a14 100644
--- a/man/weston.ini.man
+++ b/man/weston.ini.man
@@ -669,6 +669,19 @@ only for remote outputs.
 NOTE: The native outputs created by the DRM backend using the 'clone-of'
 are for cloning the outputs, and not sharing or mirroring. See also
 .BR weston-drm(7).
+.TP 7
+.BI "vrr-mode=" mode
+Sets the variable refresh rate mode of the display.
+The mode can be one of the following strings:
+.PP
+.RS 10
+.nf
+.BR  "none                 " "variable refresh rate is disabled"
+.BR  "game                 " "game variable refresh rate"
+.fi
+.RE
+.IP
+Defaults to "none".
 .\"---------------------------------------------------------------------
 .SH "INPUT-METHOD SECTION"
 .TP 7