On some models supported by ideapad-laptop, the HW/FW can remember the
state of keyboard backlight among boots. However, it is always turned
off while shutting down, as a side effect of the LED class device
unregistering sequence.

This is inconvenient for users who always prefer turning on the
keyboard backlight. Thus, set LED_RETAIN_AT_SHUTDOWN on the LED class
device so that the state of keyboard backlight gets remembered, which
also aligns with the behavior of manufacturer utilities on Windows.

Fixes: 503325f84bc0 ("platform/x86: ideapad-laptop: add keyboard backlight control support")
Cc: stable@vger.kernel.org
Signed-off-by: Rong Zhang <i@rong.moe>
---
 drivers/platform/x86/ideapad-laptop.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
index 62a72b09fc3a..edb9d2fb02ec 100644
--- a/drivers/platform/x86/ideapad-laptop.c
+++ b/drivers/platform/x86/ideapad-laptop.c
@@ -1669,7 +1669,7 @@ static int ideapad_kbd_bl_init(struct ideapad_private *priv)
 	priv->kbd_bl.led.name                    = "platform::" LED_FUNCTION_KBD_BACKLIGHT;
 	priv->kbd_bl.led.brightness_get          = ideapad_kbd_bl_led_cdev_brightness_get;
 	priv->kbd_bl.led.brightness_set_blocking = ideapad_kbd_bl_led_cdev_brightness_set;
-	priv->kbd_bl.led.flags                   = LED_BRIGHT_HW_CHANGED;
+	priv->kbd_bl.led.flags                   = LED_BRIGHT_HW_CHANGED | LED_RETAIN_AT_SHUTDOWN;
 
 	err = led_classdev_register(&priv->platform_device->dev, &priv->kbd_bl.led);
 	if (err)
-- 
2.50.0

Hi,

On 7-Jul-25 6:38 PM, Rong Zhang wrote:
> On some models supported by ideapad-laptop, the HW/FW can remember the
> state of keyboard backlight among boots. However, it is always turned
> off while shutting down, as a side effect of the LED class device
> unregistering sequence.
> 
> This is inconvenient for users who always prefer turning on the
> keyboard backlight. Thus, set LED_RETAIN_AT_SHUTDOWN on the LED class
> device so that the state of keyboard backlight gets remembered, which
> also aligns with the behavior of manufacturer utilities on Windows.
> 
> Fixes: 503325f84bc0 ("platform/x86: ideapad-laptop: add keyboard backlight control support")
> Cc: stable@vger.kernel.org
> Signed-off-by: Rong Zhang <i@rong.moe>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hansg@kernel.org>

Regards,

Hans




> ---
>  drivers/platform/x86/ideapad-laptop.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
> index 62a72b09fc3a..edb9d2fb02ec 100644
> --- a/drivers/platform/x86/ideapad-laptop.c
> +++ b/drivers/platform/x86/ideapad-laptop.c
> @@ -1669,7 +1669,7 @@ static int ideapad_kbd_bl_init(struct ideapad_private *priv)
>  	priv->kbd_bl.led.name                    = "platform::" LED_FUNCTION_KBD_BACKLIGHT;
>  	priv->kbd_bl.led.brightness_get          = ideapad_kbd_bl_led_cdev_brightness_get;
>  	priv->kbd_bl.led.brightness_set_blocking = ideapad_kbd_bl_led_cdev_brightness_set;
> -	priv->kbd_bl.led.flags                   = LED_BRIGHT_HW_CHANGED;
> +	priv->kbd_bl.led.flags                   = LED_BRIGHT_HW_CHANGED | LED_RETAIN_AT_SHUTDOWN;
>  
>  	err = led_classdev_register(&priv->platform_device->dev, &priv->kbd_bl.led);
>  	if (err)