Re: [RFC][Update 2][PATCH 1/4] ACPI / PM: Export power states of ACPI devices via sysfs

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Jan 21, 2013 at 02:04:32PM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> Make it possible to retrieve the current power state of a device with
> ACPI power management from user space via sysfs by adding a new
> attribute power_state to the sysfs directory associated with the
> struct acpi_device object representing the device's ACPI node.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>  Documentation/ABI/testing/sysfs-devices-power_state |   21 ++++++++++++++
>  drivers/acpi/scan.c                                 |   29 +++++++++++++++++++-
>  2 files changed, 49 insertions(+), 1 deletion(-)
> 
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -178,6 +178,23 @@ err_out:
>  }
>  EXPORT_SYMBOL(acpi_bus_hot_remove_device);
>  
> +static ssize_t power_state_show(struct device *dev,
> +				struct device_attribute *attr, char *buf)
> +{
> +	struct acpi_device *adev = to_acpi_device(dev);
> +	int state;
> +	int ret;
> +
> +	ret = acpi_device_get_power(adev, &state);
> +	if (ret)
> +		return ret;
> +
> +	return sprintf(buf, "%s %s\n", acpi_power_state_string(state),
> +		       acpi_power_state_string(adev->power.state));
> +}

You are showing 2 different things here in a single sysfs file, which is
really frowned apon.  Any chance to split this up into two different
sysfs files instead?

thanks,

greg k-h