linux-kernel - Re: [PATCH v10 04/14] platform/x86: alienware-wmi: Refactor LED control methods

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Message-ID: <Z6t76t_4nIXwFX5Q@black.fi.intel.com>
Date: Tue, 11 Feb 2025 18:33:46 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Kurt Borja <kuurtb@...il.com>
Cc: platform-driver-x86@...r.kernel.org,
	Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
	Armin Wolf <W_Armin@....de>,
	Mario Limonciello <mario.limonciello@....com>,
	Hans de Goede <hdegoede@...hat.com>, Dell.Client.Kernel@...l.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v10 04/14] platform/x86: alienware-wmi: Refactor LED
 control methods

On Fri, Feb 07, 2025 at 10:46:00AM -0500, Kurt Borja wrote:
> Both WMI devices handled by this module specify a distinct interface for
> LED control. Previously this module handled this by dynamically adapting
> arguments passed to wmi_evaluate_method() based on the `interface`
> global variable.
> 
> To avoid the use of global variables, and enable the migration to
> non-deprecated WMI methods, let the WMI drivers define upd_led and
> upd_brightness operations, which completely replace
> alienware_update_led() and wmax_brightness().
> 
> Also define alienware_wmi_command(), which serves as a wrapper for
> wmidev_evaluate_method(). This new method is very similar to
> alienware_wmax_command() but is WMI device agnostic.

...

> +static int alienware_wmi_command(struct wmi_device *wdev, u32 method_id,
> +				 void *in_args, size_t in_size, u32 *out_data)
> +{
> +	struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
> +	struct acpi_buffer in = {in_size, in_args};
> +	acpi_status ret;
> +
> +	ret = wmidev_evaluate_method(wdev, 0, method_id, &in, out_data ? &out : NULL);
> +	if (ACPI_FAILURE(ret))
> +		return -EIO;
> +
> +	union acpi_object *obj __free(kfree) = out.pointer;

Actually we have ACPI_FREE(), but it's not big deal (as of today) to use kfree().

> +	if (out_data) {
> +		if (obj && obj->type == ACPI_TYPE_INTEGER)
> +			*out_data = (u32)obj->integer.value;

Unneeded casting.

> +		else
> +			return -ENOMSG;
> +	}
> +
> +	return 0;
> +}

...

> +	if (legacy_args.state != LEGACY_RUNNING) {

With inverted conditional and duplicated line it will all look better.

> +		legacy_args.state = priv->lighting_control_state;
> +
> +		input.length = sizeof(legacy_args);
> +		input.pointer = &legacy_args;
> +
> +		status = wmi_evaluate_method(LEGACY_POWER_CONTROL_GUID, 0,
> +					     location + 1, &input, NULL);
> +		if (ACPI_FAILURE(status))
> +			return -EIO;
> +
> +		return 0;
> +	}
> +
> +	return alienware_wmi_command(wdev, location + 1, &legacy_args,
> +				     sizeof(legacy_args), NULL);

...

> +static int wmax_wmi_update_brightness(struct alienfx_priv *priv,
> +				      struct wmi_device *wdev, u8 brightness)
> +{
> +	struct wmax_brightness_args in_args = {
> +		.led_mask = 0xFF,

GENMASK()?

> +		.percentage = brightness,
> +	};
> +
> +	return alienware_wmi_command(wdev, WMAX_METHOD_BRIGHTNESS, &in_args,
> +				     sizeof(in_args), NULL);
> +}

-- 
With Best Regards,
Andy Shevchenko