Re: [PATCH v6 3/3] HID: lamparray: blank lamps across suspend and restore on resume

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] hid: lamparray: blink timer overwrites blanked state during suspend
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commit 0480546fa780aefd04da86e31cbb23c2cb7e6a3d
Author: Cristian Mazzotta <cmmazzo@icloud.com>

HID: lamparray: blank lamps across suspend and restore on resume

This commit adds power management callbacks to blank lamparray devices
during system suspend by writing zeroes to the color channels. It also
introduces a resume function to explicitly transition the device out of
autonomous mode and restore its cached color state.

> diff --git a/drivers/hid/hid-lamparray.c b/drivers/hid/hid-lamparray.c
> index acc00950495bf..c7d4d3d1b02d3 100644
> --- a/drivers/hid/hid-lamparray.c
> +++ b/drivers/hid/hid-lamparray.c

[ ... ]

> +void lamparray_suspend(struct lamparray *la)
> +{
> +	struct lamparray_device *ldev;
> +
> +	if (!la)
> +		return;
> +
> +	ldev = &la->ldev;
> +
> +	if (!ldev->use_leds_uapi)
> +		return;
> +
> +	mutex_lock(&ldev->dev_lock);
> +	lamparray_hw_set_state(ldev, 0, 0, 0, 0);
> +	mutex_unlock(&ldev->dev_lock);

[Severity: Medium]
Will active LED software blink timers continue to fire during system
suspend and overwrite this blanked state?

If a userspace application or trigger enables software blinking on the
lamparray LED classdev before system suspend (e.g. s2idle), the timer
can continue to queue work to leds_wq. This will call
lamparray_hw_set_state() and overwrite the blanked (0,0,0,0) state set
here, causing high power draw and undermining the intent of this function.

Does the lamparray LED classdev initialization need to set the
LED_CORE_SUSPENDRESUME flag so the LED subsystem correctly applies
LED_SUSPENDED and prevents timers from queuing new brightness updates
during suspend?

> +
> +	hid_hw_wait(ldev->hdev);
> +}
> +EXPORT_SYMBOL_GPL(lamparray_suspend);

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Sashiko AI review · https://sashiko.dev/#/patchset/20260916144838.456239-1-aer@tuxedocomputers.com?part=3