platform/x86: asus-wmi: use brightness_set_blocking() for kbd led

kbd_led_set() can sleep, and so may not be used as the brightness_set()
callback.

Otherwise using this led with a trigger leads to system hangs
accompanied by:
BUG: scheduling while atomic: acpi_fakekeyd/2588/0x00000003
CPU: 4 UID: 0 PID: 2588 Comm: acpi_fakekeyd Not tainted 6.17.9+deb14-amd64 #1 PREEMPT(lazy)  Debian 6.17.9-1
Hardware name: ASUSTeK COMPUTER INC. ASUS EXPERTBOOK B9403CVAR/B9403CVAR, BIOS B9403CVAR.311 12/24/2024
Call Trace:
 <TASK>
 [...]
 schedule_timeout+0xbd/0x100
 __down_common+0x175/0x290
 down_timeout+0x67/0x70
 acpi_os_wait_semaphore+0x57/0x90
 [...]
 asus_wmi_evaluate_method3+0x87/0x190 [asus_wmi]
 led_trigger_event+0x3f/0x60
 [...]

Fixes: 9fe44fc98ce4 ("platform/x86: asus-wmi: Simplify the keyboard brightness updating process")
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Denis Benato <benato.denis96@gmail.com>
Link: https://patch.msgid.link/20251129101307.18085-3-anton@khirnov.net
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 64cfc0bf98dd43a45c8053fb7789e37901a29ac3..4aec7ec692501cb02ed84f9aeb91aa69139aedb4 100644 (file)
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -1704,14 +1704,14 @@ static void do_kbd_led_set(struct led_classdev *led_cdev, int value)
        kbd_led_update(asus);
 }
 
-static void kbd_led_set(struct led_classdev *led_cdev,
-                       enum led_brightness value)
+static int kbd_led_set(struct led_classdev *led_cdev, enum led_brightness value)
 {
        /* Prevent disabling keyboard backlight on module unregister */
        if (led_cdev->flags & LED_UNREGISTERING)
-               return;
+               return 0;
 
        do_kbd_led_set(led_cdev, value);
+       return 0;
 }
 
 static void kbd_led_set_by_kbd(struct asus_wmi *asus, enum led_brightness value)
@@ -1887,7 +1887,7 @@ static int asus_wmi_led_init(struct asus_wmi *asus)
                asus->kbd_led_wk = led_val;
                asus->kbd_led.name = "asus::kbd_backlight";
                asus->kbd_led.flags = LED_BRIGHT_HW_CHANGED;
-               asus->kbd_led.brightness_set = kbd_led_set;
+               asus->kbd_led.brightness_set_blocking = kbd_led_set;
                asus->kbd_led.brightness_get = kbd_led_get;
                asus->kbd_led.max_brightness = 3;