Support setting the X3D V-Cache Mode

util/x3dmodectl.c

@@ -0,0 +1,171 @@
+/*
+
+Copyright (c) 2017-2025, Feral Interactive and the GameMode contributors
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+ * Neither the name of Feral Interactive nor the names of its contributors
+   may be used to endorse or promote products derived from this software
+   without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+
+#define _GNU_SOURCE
+
+#include "common-logging.h"
+
+#include <errno.h>
+#include <glob.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define X3D_MODE_GLOB_PATTERN "/sys/bus/platform/drivers/amd_x3d_vcache/*/amd_x3d_mode"
+
+static char x3d_mode_path[PATH_MAX] = { 0 };
+
+/**
+ * Find and set the x3d mode sysfs path
+ */
+static bool find_x3d_mode_path(void)
+{
+	if (x3d_mode_path[0] != '\0') {
+		return access(x3d_mode_path, F_OK) == 0;
+	}
+
+	glob_t glob_result;
+	if (glob(X3D_MODE_GLOB_PATTERN, GLOB_NOSORT, NULL, &glob_result) != 0) {
+		return false;
+	}
+
+	if (glob_result.gl_pathc > 0) {
+		strncpy(x3d_mode_path, glob_result.gl_pathv[0], PATH_MAX - 1);
+		x3d_mode_path[PATH_MAX - 1] = '\0';
+	}
+
+	globfree(&glob_result);
+	return x3d_mode_path[0] != '\0' && access(x3d_mode_path, F_OK) == 0;
+}
+
+/**
+ * Check if x3d mode control is available
+ */
+static bool x3d_mode_available(void)
+{
+	return find_x3d_mode_path();
+}
+
+/**
+ * Return the current x3d mode
+ */
+static const char *get_x3d_mode(void)
+{
+	static char mode[64] = { 0 };
+	memset(mode, 0, sizeof(mode));
+
+	if (!x3d_mode_available()) {
+		return "unavailable";
+	}
+
+	FILE *f = fopen(x3d_mode_path, "r");
+	if (!f) {
+		LOG_ERROR("Failed to open x3d mode file for read %s: %s\n", x3d_mode_path, strerror(errno));
+		return "error";
+	}
+
+	if (fgets(mode, sizeof(mode), f) != NULL) {
+		/* Remove trailing newline */
+		char *newline = strchr(mode, '\n');
+		if (newline) {
+			*newline = '\0';
+		}
+	} else {
+		LOG_ERROR("Failed to read x3d mode from %s: %s\n", x3d_mode_path, strerror(errno));
+		fclose(f);
+		return "error";
+	}
+
+	fclose(f);
+	return mode;
+}
+
+/**
+ * Set the x3d mode to the specified value
+ */
+static int set_x3d_mode(const char *value)
+{
+	if (!x3d_mode_available()) {
+		LOG_ERROR("AMD x3D mode control is not available on this system\n");
+		return EXIT_FAILURE;
+	}
+
+	/* Validate the mode value */
+	if (strcmp(value, "frequency") != 0 && strcmp(value, "cache") != 0) {
+		LOG_ERROR("Invalid x3d mode '%s'. Valid modes are 'frequency' or 'cache'\n", value);
+		return EXIT_FAILURE;
+	}
+
+	FILE *f = fopen(x3d_mode_path, "w");
+	if (!f) {
+		LOG_ERROR("Failed to open x3d mode file for write %s: %s\n",
+		          x3d_mode_path,
+		          strerror(errno));
+		return EXIT_FAILURE;
+	}
+
+	int res = fprintf(f, "%s\n", value);
+	if (res < 0) {
+		LOG_ERROR("Failed to set x3d mode to %s: %s\n", value, strerror(errno));
+		fclose(f);
+		return EXIT_FAILURE;
+	}
+
+	fclose(f);
+	return EXIT_SUCCESS;
+}
+
+/**
+ * Main entry point, dispatch to the appropriate helper
+ */
+int main(int argc, char *argv[])
+{
+	if (argc == 2 && strncmp(argv[1], "get", 3) == 0) {
+		printf("%s", get_x3d_mode());
+	} else if (argc == 3 && strncmp(argv[1], "set", 3) == 0) {
+		const char *value = argv[2];
+
+		if (geteuid() != 0) {
+			LOG_ERROR("This program must be run as root\n");
+			return EXIT_FAILURE;
+		}
+
+		return set_x3d_mode(value);
+	} else {
+		fprintf(stderr, "usage: x3dmodectl [get] [set VALUE]\n");
+		fprintf(stderr, "where VALUE can be 'frequency' or 'cache'\n");
+		return EXIT_FAILURE;
+	}
+
+	return EXIT_SUCCESS;
+}