Message-ID: <e8a44866-602c-47bb-8b11-7ba59c3d346f@gmx.de>
Date: Thu, 6 Mar 2025 23:35:38 +0100
From: Armin Wolf <W_Armin@....de>
To: Kurt Borja <kuurtb@...il.com>,
 Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: Hans de Goede <hdegoede@...hat.com>, platform-driver-x86@...r.kernel.org,
 Dell.Client.Kernel@...l.com, linux-kernel@...r.kernel.org,
 Guenter Roeck <linux@...ck-us.net>, Jean Delvare <jdelvare@...e.com>,
 linux-hwmon@...r.kernel.org
Subject: Re: [PATCH v3 08/10] platform/x86: alienware-wmi-wmax: Add support
 for manual fan control

Am 06.03.25 um 01:56 schrieb Kurt Borja:

> All models with the "AWCC" WMAX device support a way of manually
> controlling fans.
>
> The PWM duty cycle of a fan can't be controlled directly. Instead the
> AWCC interface let's us tune a PWM `boost` value, which has the
> following empirically discovered, aproximate behavior over the PWM
> value:
>
> 	pwm = pwm_base + (pwm_boost / 255) * (pwm_max - pwm_base)
>
> Where the pwm_base is the locked PWM value controlled by the FW and
> pwm_boost is a value between 0 and 255.
>
> Expose this pwm_boost knob as a custom HWMON attribute.
>
> Cc: Guenter Roeck <linux@...ck-us.net>
> Cc: Jean Delvare <jdelvare@...e.com>
> Cc: linux-hwmon@...r.kernel.org
> Signed-off-by: Kurt Borja <kuurtb@...il.com>
> ---
>   drivers/platform/x86/dell/alienware-wmi-wmax.c | 223 ++++++++++++++++++++++++-
>   1 file changed, 220 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/platform/x86/dell/alienware-wmi-wmax.c b/drivers/platform/x86/dell/alienware-wmi-wmax.c
> index 20cf3371ee3c0e1ea038b3ca517e831f3b30dc29..de4e8f177aadc9552b05cc732e41ee458b761143 100644
> --- a/drivers/platform/x86/dell/alienware-wmi-wmax.c
> +++ b/drivers/platform/x86/dell/alienware-wmi-wmax.c
> @@ -13,8 +13,11 @@
>   #include <linux/bits.h>
>   #include <linux/dmi.h>
>   #include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/minmax.h>
>   #include <linux/moduleparam.h>
>   #include <linux/platform_profile.h>
> +#include <linux/pm.h>
>   #include <linux/units.h>
>   #include <linux/wmi.h>
>   #include "alienware-wmi.h"
> @@ -179,10 +182,12 @@ enum AWCC_THERMAL_INFORMATION_OPERATIONS {
>   	AWCC_OP_GET_FAN_MIN_RPM			= 0x08,
>   	AWCC_OP_GET_FAN_MAX_RPM			= 0x09,
>   	AWCC_OP_GET_CURRENT_PROFILE		= 0x0B,
> +	AWCC_OP_GET_FAN_BOOST			= 0x0C,
>   };
>
>   enum AWCC_THERMAL_CONTROL_OPERATIONS {
>   	AWCC_OP_ACTIVATE_PROFILE		= 0x01,
> +	AWCC_OP_SET_FAN_BOOST			= 0x02,
>   };
>
>   enum AWCC_GAME_SHIFT_STATUS_OPERATIONS {
> @@ -248,6 +253,7 @@ struct awcc_fan_data {
>   	u32 total_temps;
>   	u32 min_rpm;
>   	u32 max_rpm;
> +	u8 suspend_cache;
>   	u8 id;
>   };
>
> @@ -627,6 +633,17 @@ static inline int awcc_op_get_temperature(struct wmi_device *wdev, u8 temp_id, u
>   		.arg3 = 0,
>   	};
>
> +	return __awcc_wmi_command(wdev, AWCC_METHOD_THERMAL_INFORMATION, &args, out);
> +}
> +
> +static inline int awcc_op_get_fan_boost(struct wmi_device *wdev, u8 fan_id, u32 *out)
> +{
> +	struct wmax_u32_args args = {
> +		.operation = AWCC_OP_GET_FAN_BOOST,
> +		.arg1 = fan_id,
> +		.arg2 = 0,
> +		.arg3 = 0,
> +	};
>
>   	return __awcc_wmi_command(wdev, AWCC_METHOD_THERMAL_INFORMATION, &args, out);
>   }
> @@ -656,6 +673,19 @@ static inline int awcc_op_activate_profile(struct wmi_device *wdev, u8 profile)
>   	return __awcc_wmi_command(wdev, AWCC_METHOD_THERMAL_CONTROL, &args, &out);
>   }
>
> +static int awcc_op_set_fan_boost(struct wmi_device *wdev, u8 fan_id, u8 boost)
> +{
> +	struct wmax_u32_args args = {
> +		.operation = AWCC_OP_SET_FAN_BOOST,
> +		.arg1 = fan_id,
> +		.arg2 = boost,
> +		.arg3 = 0,
> +	};
> +	u32 out;
> +
> +	return __awcc_wmi_command(wdev, AWCC_METHOD_THERMAL_CONTROL, &args, &out);
> +}
> +
>   static int awcc_profile_id_to_pprof(u32 id, enum platform_profile_option *profile)
>   {
>   	switch (id) {
> @@ -717,6 +747,7 @@ static int awcc_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
>   			   u32 attr, int channel, long *val)
>   {
>   	struct awcc_priv *priv = dev_get_drvdata(dev);
> +	enum platform_profile_option profile;
>   	struct awcc_fan_data *fan;
>   	u32 state;
>   	int ret;
> @@ -765,6 +796,28 @@ static int awcc_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
>   		fan = priv->fan_data[channel];
>
>   		switch (attr) {
> +		case hwmon_pwm_enable:
> +			ret = awcc_op_get_current_profile(priv->wdev, &state);
> +			if (ret)
> +				return ret;
> +
> +			ret = awcc_profile_id_to_pprof(state, &profile);
> +			if (ret)
> +				return ret;
> +
> +			switch (profile) {
> +			case PLATFORM_PROFILE_PERFORMANCE:

The hwmon sysfs docs say that 0 means that the fan is spinning at maximum speed. Does PLATFORM_PROFILE_PERFORMANCE
guarantee that all fans are always spinning at maximum speed?

If no then i suggest to drop support for 0.

> +				*val = 0;
> +				break;
> +			case PLATFORM_PROFILE_CUSTOM:
> +				*val = 1;
> +				break;
> +			default:
> +				*val = 2;
> +				break;
> +			}
> +
> +			break;
>   		case hwmon_pwm_auto_channels_temp:
>   			bitmap_copy(val, fan->auto_channels_temp, BITS_PER_LONG);
>   			break;
> @@ -840,10 +893,48 @@ static int awcc_hwmon_read_string(struct device *dev, enum hwmon_sensor_types ty
>   	return 0;
>   }
>
> +
> +static int awcc_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
> +			    u32 attr, int channel, long val)
> +{
> +	struct awcc_priv *priv = dev_get_drvdata(dev);
> +	int ret;
> +
> +	switch (type) {
> +	case hwmon_pwm:
> +		switch (attr) {
> +		case hwmon_pwm_enable:
> +			/*
> +			 * We don't want to duplicate platform profile logic, so
> +			 * we only allow enabling manual fan control
> +			 */

I do not think that having pwm1_enable brings any benefit, as the pwmX_boost attributes
behave differently than pwmX attributes. I think it would be enough to document that
pwmX_boost settings will only reliably work when the custom platform profile is selected.

> +			if (val != 1)
> +				return -EINVAL;
> +
> +			ret = awcc_op_activate_profile(priv->wdev, AWCC_SPECIAL_PROFILE_CUSTOM);
> +			if (ret)
> +				return ret;
> +
> +			if (priv->ppdev)
> +				platform_profile_notify(priv->ppdev);
> +			break;
> +		default:
> +			return -EOPNOTSUPP;
> +		}
> +
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	return 0;
> +}
> +
>   static const struct hwmon_ops awcc_hwmon_ops = {
>   	.is_visible = awcc_hwmon_is_visible,
>   	.read = awcc_hwmon_read,
>   	.read_string = awcc_hwmon_read_string,
> +	.write = awcc_hwmon_write,
>   };
>
>   static const struct hwmon_channel_info * const awcc_hwmon_info[] = {
> @@ -864,7 +955,7 @@ static const struct hwmon_channel_info * const awcc_hwmon_info[] = {
>   			   HWMON_F_LABEL | HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX
>   			   ),
>   	HWMON_CHANNEL_INFO(pwm,
> -			   HWMON_PWM_AUTO_CHANNELS_TEMP,
> +			   HWMON_PWM_AUTO_CHANNELS_TEMP | HWMON_PWM_ENABLE,
>   			   HWMON_PWM_AUTO_CHANNELS_TEMP,
>   			   HWMON_PWM_AUTO_CHANNELS_TEMP,
>   			   HWMON_PWM_AUTO_CHANNELS_TEMP,
> @@ -879,6 +970,75 @@ static const struct hwmon_chip_info awcc_hwmon_chip_info = {
>   	.info = awcc_hwmon_info,
>   };
>
> +static ssize_t pwm_boost_show(struct device *dev, struct device_attribute *attr,
> +			      char *buf)
> +{
> +	int ret, index = to_sensor_dev_attr(attr)->index;

Please initialize "index" on a separate line, can remember the reverse xmas-tree order for variables.

> +	struct awcc_priv *priv = dev_get_drvdata(dev);
> +	struct awcc_fan_data *fan = priv->fan_data[index];
> +	u32 boost;
> +
> +	ret = awcc_op_get_fan_boost(priv->wdev, fan->id, &boost);
> +	if (ret)
> +		return ret;
> +
> +	return sysfs_emit(buf, "%u\n", boost);
> +}
> +
> +static ssize_t pwm_boost_store(struct device *dev, struct device_attribute *attr,
> +			       const char *buf, size_t count)
> +{
> +	int ret, index = to_sensor_dev_attr(attr)->index;
> +	struct awcc_priv *priv = dev_get_drvdata(dev);
> +	struct awcc_fan_data *fan = priv->fan_data[index];
> +	unsigned long val;
> +
> +	ret = kstrtoul(buf, 0, &val);
> +	if (ret)
> +		return ret;
> +
> +	ret = awcc_op_set_fan_boost(priv->wdev, fan->id, clamp_val(val, 0, 255));
> +
> +	return ret ? ret : count;
> +}
> +
> +static SENSOR_DEVICE_ATTR_RW(pwm1_boost, pwm_boost, 0);
> +static SENSOR_DEVICE_ATTR_RW(pwm2_boost, pwm_boost, 1);
> +static SENSOR_DEVICE_ATTR_RW(pwm3_boost, pwm_boost, 2);
> +static SENSOR_DEVICE_ATTR_RW(pwm4_boost, pwm_boost, 3);

Since those attributes are working differently than the standard pwm attributes, i suggest to
instead name them fanX_boost.

> +
> +static umode_t pwm_boost_attr_visible(struct kobject *kobj, struct attribute *attr, int n)
> +{
> +	struct awcc_priv *priv = dev_get_drvdata(kobj_to_dev(kobj));
> +
> +	return n < priv->fan_count ? attr->mode : 0;
> +}
> +
> +static bool pwm_boost_group_visible(struct kobject *kobj)
> +{
> +	return true;
> +}
> +
> +DEFINE_SYSFS_GROUP_VISIBLE(pwm_boost);
> +
> +static struct attribute *fan_boost_attrs[] = {
> +	&sensor_dev_attr_pwm1_boost.dev_attr.attr,
> +	&sensor_dev_attr_pwm2_boost.dev_attr.attr,
> +	&sensor_dev_attr_pwm3_boost.dev_attr.attr,
> +	&sensor_dev_attr_pwm4_boost.dev_attr.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group pwm_boost_group = {
> +	.attrs = fan_boost_attrs,
> +	.is_visible = SYSFS_GROUP_VISIBLE(pwm_boost),
> +};
> +
> +static const struct attribute_group *awcc_hwmon_groups[] = {
> +	&pwm_boost_group,
> +	NULL
> +};
> +
>   static int awcc_hwmon_temps_init(struct wmi_device *wdev)
>   {
>   	struct awcc_priv *priv = dev_get_drvdata(&wdev->dev);
> @@ -1011,12 +1171,50 @@ static int awcc_hwmon_init(struct wmi_device *wdev)
>   	if (ret)
>   		return ret;
>
> -	priv->hwdev = devm_hwmon_device_register_with_info(&wdev->dev, "alienware_wmi", priv,
> -							   &awcc_hwmon_chip_info, NULL);
> +	priv->hwdev = devm_hwmon_device_register_with_info(&wdev->dev, "alienware_wmi",
> +							   priv, &awcc_hwmon_chip_info,
> +							   awcc_hwmon_groups);
>
>   	return PTR_ERR_OR_ZERO(priv->hwdev);
>   }
>
> +static void awcc_hwmon_suspend(struct device *dev)
> +{
> +	struct awcc_priv *priv = dev_get_drvdata(dev);
> +	struct awcc_fan_data *fan;
> +	unsigned int i;
> +	u32 boost;
> +	int ret;
> +
> +	for (i = 0; i < priv->fan_count; i++) {
> +		fan = priv->fan_data[i];
> +
> +		ret = awcc_thermal_information(priv->wdev, AWCC_OP_GET_FAN_BOOST,
> +					       fan->id, &boost);
> +		if (ret)
> +			fan->suspend_cache = 0;

Please at least log a warning here that the fan boost value can not be restored properly.

> +		else
> +			fan->suspend_cache = clamp_val(boost, 0, 255);
> +
> +		awcc_op_set_fan_boost(priv->wdev, fan->id, 0);
> +	}
> +}
> +
> +static void awcc_hwmon_resume(struct device *dev)
> +{
> +
> +	struct awcc_priv *priv = dev_get_drvdata(dev);
> +	struct awcc_fan_data *fan;
> +	unsigned int i;
> +
> +	for (i = 0; i < priv->fan_count; i++) {
> +		fan = priv->fan_data[i];
> +
> +		if (fan->suspend_cache)

How does the driver restore fan boost settings with a value of 0?

Thanks,
Armin Wolf

> +			awcc_op_set_fan_boost(priv->wdev, fan->id, fan->suspend_cache);
> +	}
> +}
> +
>   /*
>    * Thermal Profile control
>    *  - Provides thermal profile control through the Platform Profile API
> @@ -1233,6 +1431,24 @@ static int wmax_wmi_probe(struct wmi_device *wdev, const void *context)
>   	return ret;
>   }
>
> +static int wmax_wmi_suspend(struct device *dev)
> +{
> +	if (awcc->hwmon)
> +		awcc_hwmon_suspend(dev);
> +
> +	return 0;
> +}
> +
> +static int wmax_wmi_resume(struct device *dev)
> +{
> +	if (awcc->hwmon)
> +		awcc_hwmon_resume(dev);
> +
> +	return 0;
> +}
> +
> +DEFINE_SIMPLE_DEV_PM_OPS(wmax_wmi_pm_ops, wmax_wmi_suspend, wmax_wmi_resume);
> +
>   static const struct wmi_device_id alienware_wmax_device_id_table[] = {
>   	{ WMAX_CONTROL_GUID, NULL },
>   	{ },
> @@ -1243,6 +1459,7 @@ static struct wmi_driver alienware_wmax_wmi_driver = {
>   	.driver = {
>   		.name = "alienware-wmi-wmax",
>   		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
> +		.pm = pm_sleep_ptr(&wmax_wmi_pm_ops),
>   	},
>   	.id_table = alienware_wmax_device_id_table,
>   	.probe = wmax_wmi_probe,
>

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