Re: [PATCH 2/3] platform: arm64: Add Lenovo ThinkPad X13s EC driver

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] pm: system suspend aborted on non-critical backlight read failure
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commit d53f4ca8cee991526718fae25d7c38b7a3993fc8
Author: Clover <alex@ironrobin.net>

platform: arm64: Add Lenovo ThinkPad X13s EC driver

Add a standalone driver for the Lenovo ThinkPad X13s embedded controller,
providing keyboard-backlight control and notifications of firmware-driven
brightness changes.

> diff --git a/drivers/platform/arm64/lenovo-thinkpad-x13s.c b/drivers/platform/arm64/lenovo-thinkpad-x13s.c
> new file mode 100644
> index 0000000000000..066f6e300d38f
> --- /dev/null
> +++ b/drivers/platform/arm64/lenovo-thinkpad-x13s.c

[ ... ]

> +static int x13s_suspend(struct device *dev)
> +{
> +	struct x13s_ec *ec = dev_get_drvdata(dev);
> +	int ret;
> +
> +	/* Finish in-flight access while the GENI parent is still usable. */
> +	mutex_lock(&ec->lock);
> +	if (ec->suspended) {
> +		ret = -EBUSY;
> +		goto out;
> +	}
> +	/* Capture hardware state before firmware can reset the backlight. */
> +	ret = x13s_brightness(ec);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to save backlight brightness: %d\n", ret);
> +		goto out;
> +	}

[Severity: High]
Could this abort the entire system suspend if the non-critical keyboard
backlight read fails? If x13s_brightness() fails due to a transient bus
error or returns a reserved state (-EINVAL), returning this error to the
PM core prevents the system from sleeping.

> +	ec->saved_brightness = ret;
> +
> +	/* DSDT: register 0x80 <- 0x55, then GPIO176 low. */
> +	ret = x13s_write(ec, X13S_EC_REG_POWER_STATE, X13S_EC_POWER_STATE_ENTER);

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260925215358.33417-1-alex@ironrobin.net?part=2