Re: [PATCH v4 2/2] leds: trigger: input-events: Restore previous brightness on input

[sashiko-bot@kernel.org]

> From: Nikolay Plastinin <plaztininikolai@gmail.com>
> 
> The trigger turns the LEDs back on with LED_FULL, which the LED core
> clamps to max_brightness. For keyboard backlights with several levels,
> such as asus::kbd_backlight, this means the backlight always comes back
> at maximum after being idle instead of at the level the user picked.
> 
> Remember the brightness per LED before turning it off and restore it on
> the next input event. Keep the level in a per-LED state struct allocated
> in activate() and freed in deactivate(), converting the simple trigger
> to a regular trigger. Pick up brightness changes made while the LED is
> on before saving the level again.
> 
> Use led_trigger_for_each_led() under guard(rcu)() for both the on and
> off paths. Skip LEDs whose activate() callback has not set up their
> state yet.
> 
> Clear trigger_data under the same lock used by the LED walker before
> freeing the per-LED state. Although normal trigger removal waits for an
> RCU grace period, the device_add_groups() error path calls deactivate()
> while the LED is still linked, so a walker must see NULL after teardown.
> 
> The previous revision was tested on an ASUS ROG Flow X13 GV302XV:
> keyboard backlight levels 1 and 2 were restored after idle timeout and
> keyboard input, and 20 trigger activate/deactivate cycles completed
> successfully.
> 
> Assisted-by: LLM
> Signed-off-by: Nikolay Plastinin <plaztininikolai@gmail.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261030-leds-input-events-brightness-v4-0-5ea0ead7480c@gmail.com?part=2