From db5e2a4ca0a7a5fe54f410590292ea2e91de6798 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Mon, 7 Nov 2022 13:43:22 +0100
Subject: [PATCH] platform/x86: thinkpad_acpi: Fix max_brightness of thinklight
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Git-commit: db5e2a4ca0a7a5fe54f410590292ea2e91de6798
Patch-mainline: v6.2-rc1
References: bsc#1210050

Thinklight has only two values, on/off so it's reasonable for
max_brightness to be 0 and 1 as if you write anything between 0 and 255
it will be 255 anyway so there's no point for it to be 255.

This may look like it is a userspace API change, but writes with
a value larget then the new max_brightness will still be accepted,
these will be silently clamped to the new max_brightness by
led_set_brightness_nosleep(). So no userspace API problems are
expected.

Reported-by: Michał Szczepaniak <m.szczepaniak.000@gmail.com>
Link: https://lore.kernel.org/platform-driver-x86/55400326-e64f-5444-94e5-22b8214d00b6@gmail.com/
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/platform/x86/thinkpad_acpi.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 4b12808bddab..cfeed1c45b54 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -5572,6 +5572,7 @@ static enum led_brightness light_sysfs_get(struct led_classdev *led_cdev)
 static struct tpacpi_led_classdev tpacpi_led_thinklight = {
 	.led_classdev = {
 		.name		= "tpacpi::thinklight",
+		.max_brightness	= 1,
 		.brightness_set_blocking = &light_sysfs_set,
 		.brightness_get	= &light_sysfs_get,
 	}
-- 
2.35.3