# \[PATCH 2/5\] HID: lenovo: Use brightness\_set\_blocking callback for setting LEDs brightness

- From: Hans de Goede \<hidden\>
- Date: 2021-02-15 20:40:07 
- List: linux-input
- Page: https://ratatoskr.run/linux-input/2021/02/8932605
- Thread: https://ratatoskr.run/linux-input/2021/02/8932603/t.md

```text
The lenovo_led_brightness_set function may sleep, so we should have the
the led_class_dev's brightness_set_blocking callback point to it, rather
then the regular brightness_set callback.

When toggle through sysfs this is not a problem, but the brightness_set
callback may be called from atomic context when using LED-triggers.

Fixes: bc04b37ea0ec ("HID: lenovo: Add ThinkPad 10 Ultrabook Keyboard support")
Signed-off-by: Hans de Goede <redacted>
---
 drivers/hid/hid-lenovo.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-lenovo.c b/drivers/hid/hid-lenovo.c
index 69d709439676..9b80b1685b53 100644
--- a/drivers/hid/hid-lenovo.c
+++ b/drivers/hid/hid-lenovo.c
@@ -777,7 +777,7 @@ static enum led_brightness lenovo_led_brightness_get(
 				: LED_OFF;
 }
 
-static void lenovo_led_brightness_set(struct led_classdev *led_cdev,
+static int lenovo_led_brightness_set(struct led_classdev *led_cdev,
 			enum led_brightness value)
 {
 	struct device *dev = led_cdev->dev->parent;
@@ -802,6 +802,8 @@ static void lenovo_led_brightness_set(struct led_classdev *led_cdev,
 		lenovo_led_set_tp10ubkbd(hdev, tp10ubkbd_led[led_nr], value);
 		break;
 	}
+
+	return 0;
 }
 
 static int lenovo_register_leds(struct hid_device *hdev)
@@ -822,7 +824,7 @@ static int lenovo_register_leds(struct hid_device *hdev)
 
 	data->led_mute.name = name_mute;
 	data->led_mute.brightness_get = lenovo_led_brightness_get;
-	data->led_mute.brightness_set = lenovo_led_brightness_set;
+	data->led_mute.brightness_set_blocking = lenovo_led_brightness_set;
 	data->led_mute.dev = &hdev->dev;
 	ret = led_classdev_register(&hdev->dev, &data->led_mute);
 	if (ret < 0)
@@ -830,7 +832,7 @@ static int lenovo_register_leds(struct hid_device *hdev)
 
 	data->led_micmute.name = name_micm;
 	data->led_micmute.brightness_get = lenovo_led_brightness_get;
-	data->led_micmute.brightness_set = lenovo_led_brightness_set;
+	data->led_micmute.brightness_set_blocking = lenovo_led_brightness_set;
 	data->led_micmute.dev = &hdev->dev;
 	ret = led_classdev_register(&hdev->dev, &data->led_micmute);
 	if (ret < 0) {
-- 
2.30.1

```