Re: [RFC PATCH 1/3] platform/x86: lenovo-wmi-other: Add Legion Go Full Speed control

[Antheas Kapenekakis]

On Fri, 21 Aug 2026 at 23:47, Aditya Dash <mradityadash@xxxxxxxxx> wrote:
>
> Selected Legion Go firmware exposes Full Speed as Other Mode feature
> 0x04020000. Capability Data does not describe this feature, so
> lenovo-wmi-other currently ignores it.

Rephrase. Legion Go devices expose .... The current driver does not
handle this ..., add support for the Full Speed attribute ...

> Probe the feature during HWMON setup on those products. If the read
> succeeds and returns a Boolean value, expose it as pwm1_enable. Value 0
> selects Full Speed, and value 2 returns fan control to firmware automatic
> mode. Reject all other values.
>
> Assisted-by: Pi:gpt-5.6-sol
> Signed-off-by: Aditya Dash <mradityadash@xxxxxxxxx>
> ---
>  .../wmi/devices/lenovo-wmi-other.rst          |   7 ++
>  drivers/platform/x86/lenovo/wmi-other.c       | 108 +++++++++++++++++-
>  2 files changed, 114 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/wmi/devices/lenovo-wmi-other.rst b/Documentation/wmi/devices/lenovo-wmi-other.rst
> index 011054d64eac..75f2deaaef16 100644
> --- a/Documentation/wmi/devices/lenovo-wmi-other.rst
> +++ b/Documentation/wmi/devices/lenovo-wmi-other.rst
> @@ -49,6 +49,13 @@ The following HWMON attributes are implemented:
>  Due to the internal RPM divisor, the current/target RPMs are rounded down to
>  its nearest multiple. The divisor itself is not necessary to be a power of two.
>
> +Legion Go fan controls
> +----------------------
> +
> +On supported Legion Go models, Other Mode feature ``0x04020000`` controls
> +Full Speed mode in firmware. The driver exposes it as ``pwm1_enable``. Value 0
> +enables Full Speed, and value 2 returns fan control to firmware.
> +
>  LENOVO_CAPABILITY_DATA_01
>  -------------------------
>
> diff --git a/drivers/platform/x86/lenovo/wmi-other.c b/drivers/platform/x86/lenovo/wmi-other.c
> index fbb32bf404f2..c180933e1d18 100644
> --- a/drivers/platform/x86/lenovo/wmi-other.c
> +++ b/drivers/platform/x86/lenovo/wmi-other.c
> @@ -32,6 +32,7 @@
>  #include <linux/component.h>
>  #include <linux/container_of.h>
>  #include <linux/device.h>
> +#include <linux/dmi.h>
>  #include <linux/export.h>
>  #include <linux/gfp_types.h>
>  #include <linux/hwmon.h>
> @@ -83,6 +84,7 @@ enum lwmi_feature_id_psu {
>         LWMI_FEATURE_ID_PSU_CHARGE_BEHAVIOUR =  0x02,
>  };
>
> +#define LWMI_FEATURE_ID_FAN_FULLSPEED 0x02
>  #define LWMI_FEATURE_ID_FAN_RPM 0x03
>
>  #define LWMI_TYPE_ID_CROSSLOAD 0x01
> @@ -102,6 +104,10 @@ enum lwmi_feature_id_psu {
>  #define LWMI_CHARGE_TYPE_STANDARD      0x00
>  #define LWMI_CHARGE_TYPE_LONGLIFE      0x01
>
> +#define LWMI_ATTR_ID_FAN_FULLSPEED                                     \
> +       lwmi_attr_id(LWMI_DEVICE_ID_FAN, LWMI_FEATURE_ID_FAN_FULLSPEED, \
> +                    LWMI_GZ_THERMAL_MODE_NONE, LWMI_TYPE_ID_NONE)
> +
>  #define LWMI_ATTR_ID_FAN_RPM(x)                                   \
>         lwmi_attr_id(LWMI_DEVICE_ID_FAN, LWMI_FEATURE_ID_FAN_RPM, \
>                      LWMI_GZ_THERMAL_MODE_NONE, LWMI_FAN_ID(x))
> @@ -115,6 +121,50 @@ enum lwmi_feature_id_psu {
>
>  static DEFINE_IDA(lwmi_om_ida);
>
> +static const struct dmi_system_id lwmi_fan_dmi_table[] = {
> +       {
> +               .ident = "Lenovo Legion Go 8APU1",
> +               .matches = {
> +                       DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +                       DMI_EXACT_MATCH(DMI_PRODUCT_VERSION, "Legion Go 8APU1"),
> +               },
> +       },
> +       {
> +               .ident = "Lenovo Legion Go S 8APU1",
> +               .matches = {
> +                       DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +                       DMI_EXACT_MATCH(DMI_PRODUCT_VERSION, "Legion Go S 8APU1"),
> +               },
> +       },
> +       {
> +               .ident = "Lenovo Legion Go S 8ARP1",
> +               .matches = {
> +                       DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +                       DMI_EXACT_MATCH(DMI_PRODUCT_VERSION, "Legion Go S 8ARP1"),
> +               },
> +       },
> +       {
> +               .ident = "Lenovo Legion Go 8ASP2",
> +               .matches = {
> +                       DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +                       DMI_EXACT_MATCH(DMI_PRODUCT_VERSION, "Legion Go 8ASP2"),
> +               },
> +       },
> +       {
> +               .ident = "Lenovo Legion Go 8AHP2",
> +               .matches = {
> +                       DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +                       DMI_EXACT_MATCH(DMI_PRODUCT_VERSION, "Legion Go 8AHP2"),
> +               },
> +       },
> +       {}
> +};

Why DMI match?

> +
> +static bool lwmi_fan_supported(void)
> +{
> +       return dmi_check_system(lwmi_fan_dmi_table);
> +}

Why not cap match? My version might help you:
https://github.com/anatase-org/patchwork/commit/3d326d36ac8839f5d6f1d3ab1885322bbdf4a3cb

Best,
Antheas

> +
>  enum attribute_property {
>         DEFAULT_VAL,
>         MAX_VAL,
> @@ -144,6 +194,7 @@ struct lwmi_om_priv {
>         int ida_id;
>
>         struct lwmi_fan_info fan_info[LWMI_FAN_NR];
> +       bool fullspeed_supported;
>
>         struct {
>                 bool capdata00_collected : 1;
> @@ -237,6 +288,38 @@ static int lwmi_om_fan_get_set(struct lwmi_om_priv *priv, int channel, u32 *val,
>         return (retval == 0 || retval == 1) ? 0 : -EIO;
>  }
>
> +static int lwmi_om_fullspeed_get(struct lwmi_om_priv *priv, long *enable)
> +{
> +       struct wmi_method_args_32 args = {
> +               .arg0 = LWMI_ATTR_ID_FAN_FULLSPEED,
> +       };
> +       u32 value;
> +       int ret;
> +
> +       ret = lwmi_dev_evaluate_int(priv->wdev, 0, LWMI_FEATURE_VALUE_GET,
> +                                   (u8 *)&args, sizeof(args), &value);
> +       if (ret)
> +               return ret;
> +
> +       if (value > 1)
> +               return -ERANGE;
> +
> +       *enable = value ? 0 : 2;
> +       return 0;
> +}
> +
> +static int lwmi_om_fullspeed_set(struct lwmi_om_priv *priv, bool fullspeed)
> +{
> +       struct wmi_method_args_32 args = {
> +               .arg0 = LWMI_ATTR_ID_FAN_FULLSPEED,
> +               .arg1 = fullspeed,
> +       };
> +
> +       /* The WMI method has no return value. */
> +       return lwmi_dev_evaluate_int(priv->wdev, 0, LWMI_FEATURE_VALUE_SET,
> +                                    (u8 *)&args, sizeof(args), NULL);
> +}
> +
>  /**
>   * lwmi_om_hwmon_is_visible() - Determine visibility of HWMON attributes
>   * @drvdata: Driver private data
> @@ -255,6 +338,10 @@ static umode_t lwmi_om_hwmon_is_visible(const void *drvdata, enum hwmon_sensor_t
>         struct lwmi_om_priv *priv = (struct lwmi_om_priv *)drvdata;
>         bool visible = false;
>
> +       if (type == hwmon_pwm && priv->fullspeed_supported && channel == 0 &&
> +           attr == hwmon_pwm_enable)
> +               return 0644;
> +
>         if (type == hwmon_fan) {
>                 if (!(priv->fan_info[channel].supported & LWMI_SUPP_VALID))
>                         return 0;
> @@ -311,6 +398,9 @@ static int lwmi_om_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
>         u32 retval = 0;
>         int err;
>
> +       if (type == hwmon_pwm && attr == hwmon_pwm_enable && channel == 0)
> +               return lwmi_om_fullspeed_get(priv, val);
> +
>         if (type == hwmon_fan) {
>                 switch (attr) {
>                 /*
> @@ -366,6 +456,17 @@ static int lwmi_om_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
>         u32 raw, min_rpm, max_rpm;
>         int err;
>
> +       if (type == hwmon_pwm && attr == hwmon_pwm_enable && channel == 0) {
> +               switch (val) {
> +               case 0:
> +                       return lwmi_om_fullspeed_set(priv, true);
> +               case 2:
> +                       return lwmi_om_fullspeed_set(priv, false);
> +               default:
> +                       return -EINVAL;
> +               }
> +       }
> +
>         if (type == hwmon_fan) {
>                 switch (attr) {
>                 case hwmon_fan_target:
> @@ -420,6 +521,7 @@ static const struct hwmon_channel_info * const lwmi_om_hwmon_info[] = {
>                            HWMON_F_MIN | HWMON_F_MAX,
>                            HWMON_F_INPUT | HWMON_F_TARGET | HWMON_F_DIV |
>                            HWMON_F_MIN | HWMON_F_MAX),
> +       HWMON_CHANNEL_INFO(pwm, HWMON_PWM_ENABLE),
>         NULL
>  };
>
> @@ -440,6 +542,7 @@ static const struct hwmon_chip_info lwmi_om_hwmon_chip_info = {
>   */
>  static void lwmi_om_hwmon_add(struct lwmi_om_priv *priv)
>  {
> +       long enable;
>         int i, valid;
>
>         if (WARN_ON(priv->hwmon_dev))
> @@ -458,6 +561,9 @@ static void lwmi_om_hwmon_add(struct lwmi_om_priv *priv)
>         if (relax_fan_constraint)
>                 dev_warn(&priv->wdev->dev, "fan RPM constraint relaxed. Use with caution\n");
>
> +       priv->fullspeed_supported =
> +               lwmi_fan_supported() && !lwmi_om_fullspeed_get(priv, &enable);
> +
>         valid = 0;
>         for (i = 0; i < LWMI_FAN_NR; i++) {
>                 if (!(priv->fan_info[i].supported & LWMI_SUPP_VALID))
> @@ -474,7 +580,7 @@ static void lwmi_om_hwmon_add(struct lwmi_om_priv *priv)
>                 }
>         }
>
> -       if (valid == 0) {
> +       if (valid == 0 && !priv->fullspeed_supported) {
>                 dev_warn(&priv->wdev->dev,
>                          "fan reporting/tuning is unsupported on this device\n");
>                 return;

This log is a wart. You dmi match anyway. Preferably, you would cap
match. Even then, silently dropping the unsupported features is
preferrable.

> --
> 2.55.0
>