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From:   koba.ko@canonical.com
To:     Matthew Garrett <mjg59@srcf.ucam.org>,
        =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali.rohar@gmail.com>,
        Darren Hart <dvhart@infradead.org>,
        Andy Shevchenko <andy@infradead.org>,
        platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org,
        Mario Limonciello <mario.limonciello@dell.com>
Subject: [PATCH] platform/x86: dell-laptop: don't register platform::micmute if the related tokens don't exist.
Date:   Thu,  7 May 2020 20:27:03 +0800
Message-Id: <20200507122703.14617-1-koba.ko@canonical.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Koba Ko <koba.ko@canonical.com>

During boot up, Error messge is issued,
"platform::micmute: Setting an LED's brightness failed (-19)",
but the device isn't presented.

Get the related tokens of SMBIOS, GLOBAL_MIC_MUTE_DISABLE/ENABLE.
If one of two tokens doesn't exist,
don't call led_classdev_register() for platform::micmute.
After that, you wouldn't see the platform::micmute in /sys/class/leds/,
and the error message wouldn't see in dmesg.

Signed-off-by: Koba Ko <koba.ko@canonical.com>
---
 drivers/platform/x86/dell-laptop.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
index 74e988f839e8..e315185dbdd6 100644
--- a/drivers/platform/x86/dell-laptop.c
+++ b/drivers/platform/x86/dell-laptop.c
@@ -2164,7 +2164,7 @@ static struct led_classdev micmute_led_cdev = {
 static int __init dell_init(void)
 {
 	struct calling_interface_token *token;
-	int max_intensity = 0;
+	int max_intensity = 0, is_micmute_exist = 0;
 	int ret;
 
 	if (!dmi_check_system(dell_device_table))
@@ -2204,10 +2204,14 @@ static int __init dell_init(void)
 
 	dell_laptop_register_notifier(&dell_laptop_notifier);
 
-	micmute_led_cdev.brightness = ledtrig_audio_get(LED_AUDIO_MICMUTE);
-	ret = led_classdev_register(&platform_device->dev, &micmute_led_cdev);
-	if (ret < 0)
-		goto fail_led;
+	if (dell_smbios_find_token(GLOBAL_MIC_MUTE_DISABLE) &&
+	    dell_smbios_find_token(GLOBAL_MIC_MUTE_ENABLE)) {
+		micmute_led_cdev.brightness = ledtrig_audio_get(LED_AUDIO_MICMUTE);
+		ret = led_classdev_register(&platform_device->dev, &micmute_led_cdev);
+		if (ret < 0)
+			goto fail_led;
+		is_micmute_exist = 1;
+	}
 
 	if (acpi_video_get_backlight_type() != acpi_backlight_vendor)
 		return 0;
@@ -2254,7 +2258,8 @@ static int __init dell_init(void)
 fail_get_brightness:
 	backlight_device_unregister(dell_backlight_device);
 fail_backlight:
-	led_classdev_unregister(&micmute_led_cdev);
+	if (is_micmute_exist)
+		led_classdev_unregister(&micmute_led_cdev);
 fail_led:
 	dell_cleanup_rfkill();
 fail_rfkill:
-- 
2.25.1