linux-kernel - Re: [PATCH v2] platform/chrome: cros_ec_lightbar: Check if ec supports suspend commands

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Message-ID: <aQPI4y-S5oN8sqWU@google.com>
Date: Thu, 30 Oct 2025 20:21:55 +0000
From: Benson Leung <bleung@...gle.com>
To: Brady Norander <bradynorander@...il.com>
Cc: chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org,
	Benson Leung <bleung@...omium.org>,
	Tzung-Bi Shih <tzungbi@...nel.org>,
	Guenter Roeck <groeck@...omium.org>
Subject: Re: [PATCH v2] platform/chrome: cros_ec_lightbar: Check if ec
 supports suspend commands

On Thu, Oct 30, 2025 at 03:59:11PM -0400, Brady Norander wrote:
> The Chromebook Pixel 2013 (Link)'s ec does not support the lightbar manual suspend commands.
> As a result, attempting to suspend the device fails and prints the following error:
> 
>     cros-ec-lightbar cros-ec-lightbar.3.auto: PM: dpm_run_callback(): platform_pm_suspend returns -22
>     cros-ec-lightbar cros-ec-lightbar.3.auto: PM: failed to suspend: error -22
>     PM: Some devices failed to suspend, or early wake event detected
> 
> Check the return value of lb_manual_suspend_ctrl in cros_ec_lightbar_probe and disable manual
> suspend control if -EINVAL is returned.
> 
> Signed-off-by: Brady Norander <bradynorander@...il.com>

Reviewed-by: Benson Leung <bleung@...omium.org>


> ---
> 
> v2:
> - Only catch -EINVAL from lb_manual_suspend_ctrl()
> 
>  drivers/platform/chrome/cros_ec_lightbar.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c
> index 87634f6921b7..893d269f6384 100644
> --- a/drivers/platform/chrome/cros_ec_lightbar.c
> +++ b/drivers/platform/chrome/cros_ec_lightbar.c
> @@ -30,6 +30,13 @@ static unsigned long lb_interval_jiffies = 50 * HZ / 1000;
>   */
>  static bool userspace_control;
>  
> +/*
> + * Whether or not the lightbar supports the manual suspend commands.
> + * The Pixel 2013 (Link) does not while all other devices with a
> + * lightbar do.
> +*/
> +static bool has_manual_suspend;
> +
>  static ssize_t interval_msec_show(struct device *dev,
>  				  struct device_attribute *attr, char *buf)
>  {
> @@ -550,7 +557,7 @@ static int cros_ec_lightbar_probe(struct platform_device *pd)
>  		return -ENODEV;
>  
>  	/* Take control of the lightbar from the EC. */
> -	lb_manual_suspend_ctrl(ec_dev, 1);
> +	has_manual_suspend = (lb_manual_suspend_ctrl(ec_dev, 1) != -EINVAL);
>  
>  	ret = sysfs_create_group(&ec_dev->class_dev.kobj,
>  				 &cros_ec_lightbar_attr_group);
> @@ -569,14 +576,15 @@ static void cros_ec_lightbar_remove(struct platform_device *pd)
>  			   &cros_ec_lightbar_attr_group);
>  
>  	/* Let the EC take over the lightbar again. */
> -	lb_manual_suspend_ctrl(ec_dev, 0);
> +	if (has_manual_suspend)
> +		lb_manual_suspend_ctrl(ec_dev, 0);
>  }
>  
>  static int __maybe_unused cros_ec_lightbar_resume(struct device *dev)
>  {
>  	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
>  
> -	if (userspace_control)
> +	if (userspace_control || !has_manual_suspend)
>  		return 0;
>  
>  	return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_RESUME);
> @@ -586,7 +594,7 @@ static int __maybe_unused cros_ec_lightbar_suspend(struct device *dev)
>  {
>  	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
>  
> -	if (userspace_control)
> +	if (userspace_control || !has_manual_suspend)
>  		return 0;
>  
>  	return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_SUSPEND);
> -- 
> 2.51.0
> 

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