From d8b01cdaee84276389af7aa0ba32099bad28c7a2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C5=99emysl=20Eric=20Janouch?= <p@janouch.name>
Date: Thu, 31 Jul 2025 21:11:45 +0200
Subject: [PATCH] eizoctl: add an option to filter by serial number

It turns out that this is actually critical when switching inputs
in certain wild setups.
---
 eizoctl.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/eizoctl.c b/eizoctl.c
index 399ad5a..810ac80 100644
--- a/eizoctl.c
+++ b/eizoctl.c
@@ -1039,6 +1039,8 @@ eizo_watch(struct eizo_monitor *m, print_fn output, print_fn error)
 static const char *usage = "Usage: %s OPTION...\n\n"
 	"  -l, --list\n"
 	"   List all connected EIZO monitors, with their serial number.\n"
+	"  -s, --serial SERIAL\n"
+	"   Only act on the monitor matching the specified serial number.\n"
 	"  -b, --brightness [+-]BRIGHTNESS\n"
 	"   Change monitor brightness; values go from 0 to 1 and may be relative.\n"
 	"  -i, --input NAME\n"
@@ -1060,6 +1062,7 @@ run(int argc, char *argv[], print_fn output, print_fn error)
 	const char *name = argv[0];
 	static struct option opts[] = {
 		{"list", no_argument, NULL, 'l'},
+		{"serial", required_argument, NULL, 's'},
 		{"brightness", required_argument, NULL, 'b'},
 		{"input", required_argument, NULL, 'i'},
 		{"restart", no_argument, NULL, 'r'},
@@ -1073,13 +1076,16 @@ run(int argc, char *argv[], print_fn output, print_fn error)
 	int quiet = 0;
 	double brightness = NAN;
 	bool list = false, relative = false, restart = false, events = false;
-	const char *port = NULL;
+	const char *serial = NULL, *port = NULL;
 	int c = 0;
-	while ((c = getopt_long(argc, argv, "lb:i:reqhV", opts, NULL)) != -1)
+	while ((c = getopt_long(argc, argv, "ls:b:i:reqhV", opts, NULL)) != -1)
 		switch (c) {
 		case 'l':
 			list = true;
 			break;
+		case 's':
+			serial = optarg;
+			break;
 		case 'b':
 			relative = *optarg == '+' || *optarg == '-';
 			if (sscanf(optarg, "%lf", &brightness) && isfinite(brightness))
@@ -1129,8 +1135,6 @@ run(int argc, char *argv[], print_fn output, print_fn error)
 	if (quiet > 1)
 		error = print_dummy;
 
-	// It should be possible to choose a particular monitor,
-	// but it is generally more useful to operate on all of them.
 	struct hid_device_info *devs = hid_enumerate(USB_VID_EIZO, 0), *p = devs;
 	for (; p; p = p->next) {
 		struct eizo_monitor m = {};
@@ -1142,6 +1146,12 @@ run(int argc, char *argv[], print_fn output, print_fn error)
 		if (list)
 			output("%s %s\n", m.product, m.serial);
 
+		// Generously assuming that different products/models
+		// don't share serial numbers,
+		// which would otherwise deserve another filtering option.
+		if (serial && strcmp(serial, m.serial))
+			goto next;
+
 		if (isfinite(brightness)) {
 			double prev = 0.;
 			if (!eizo_get_brightness(&m, &prev)) {
@@ -1186,6 +1196,7 @@ run(int argc, char *argv[], print_fn output, print_fn error)
 				error("%s\n", m.error);
 		}
 
+	next:
 		eizo_monitor_close(&m);
 	}
 	hid_free_enumeration(devs);