Re: [PATCH v3 2/6] platform/x86: lenovo-wmi-other: Limit adding attributes to supported devices

Ilpo Järvinen
2026-02-24T08:48:03Z

On Tue, 24 Feb 2026, Derek J. Clark wrote:

> Adds lwmi_is_attr_01_supported, and only creates the attribute subfolder
> if the attribute is supported by the hardware. Due to some poorly
> implemented BIOS, this is a multi-step sequence of events. This is
> because:
> - Some BIOS support getting the capability data from custom mode (0xff),
> while others only support it in no-mode (0x00).
> - Similarly, some BIOS support get/set for the current value from custom
> mode (0xff), while others only support it in no-mode (0x00).
> - Some BIOS report capability data for a method that is not fully
> implemented.
> - Some BIOS have methods fully implemented, but no complimentary
> capability data.
>
> To ensure we only expose fully implemented methods with corresponding
> capability data, we check each outcome before reporting that an
> attribute can be supported.
>
> Checking for lwmi_is_attr_01_supported during remove is not done to
> ensure that we don't attempt to call cd01 or send WMI events if one of
> the interfaces being removed was the cause of the driver unloading.
>

> While adding members to tunable_attr_01, remove unused capdata pointer
> and limit size of all ID's to the appropriate size.

Please don't mix changes like this. Create a seprate patch for it.

> Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
> Reported-by: Kurt Borja <kuurtb@gmail.com>
> Closes: https://lore.kernel.org/platform-driver-x86/DG60P3SHXR8H.3NSEHMZ6J7XRC@gmail.com/
> Signed-off-by: Derek J. Clark <derekjohn.clark@gmail.com>
> ---
> drivers/platform/x86/lenovo/wmi-other.c | 117 +++++++++++++++++++++---
> 1 file changed, 102 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/platform/x86/lenovo/wmi-other.c b/drivers/platform/x86/lenovo/wmi-other.c
> index 95886df39c8d..f3f12303e379 100644
> --- a/drivers/platform/x86/lenovo/wmi-other.c
> +++ b/drivers/platform/x86/lenovo/wmi-other.c
> @@ -545,11 +545,12 @@ static void lwmi_om_fan_info_collect_cd_fan(struct device *dev, struct cd_list *
> /* ======== fw_attributes (component: lenovo-wmi-capdata 01) ======== */
>
> struct tunable_attr_01 {
> - struct capdata01 *capdata;
> struct device *dev;
> - u32 feature_id;
> - u32 device_id;
> - u32 type_id;
> + u8 feature_id;
> + u8 device_id;
> + u8 type_id;
> + u8 cd_mode_id; /* mode arg for searching capdata */
> + u8 cv_mode_id; /* mode arg for set/get current_value */
> };
>
> static struct tunable_attr_01 ppt_pl1_spl = {
> @@ -716,7 +717,7 @@ static ssize_t attr_capdata01_show(struct kobject *kobj,
> int value, ret;
>
> attribute_id = LWMI_ATTR_ID(tunable_attr->device_id, tunable_attr->feature_id,
> - LWMI_GZ_THERMAL_MODE_CUSTOM, tunable_attr->type_id);
> + tunable_attr->cd_mode_id, tunable_attr->type_id);
>
> ret = lwmi_cd01_get_data(priv->cd01_list, attribute_id, &capdata);
> if (ret)
> @@ -782,7 +783,7 @@ static ssize_t attr_current_value_store(struct kobject *kobj,
> return -EBUSY;
>
> args.arg0 = LWMI_ATTR_ID(tunable_attr->device_id, tunable_attr->feature_id,
> - mode, tunable_attr->type_id);
> + tunable_attr->cd_mode_id, tunable_attr->type_id);
>
> ret = lwmi_cd01_get_data(priv->cd01_list, args.arg0, &capdata);
> if (ret)
> @@ -795,6 +796,8 @@ static ssize_t attr_current_value_store(struct kobject *kobj,
> if (value < capdata.min_value || value > capdata.max_value)
> return -EINVAL;
>
> + args.arg0 = LWMI_ATTR_ID(tunable_attr->device_id, tunable_attr->feature_id,
> + tunable_attr->cv_mode_id, tunable_attr->type_id);
> args.arg1 = value;
>
> ret = lwmi_dev_evaluate_int(priv->wdev, 0x0, LWMI_FEATURE_VALUE_SET,
> @@ -828,13 +831,16 @@ static ssize_t attr_current_value_show(struct kobject *kobj,
> struct lwmi_om_priv *priv = dev_get_drvdata(tunable_attr->dev);
> struct wmi_method_args_32 args;
> enum thermal_mode mode;
> - int retval;
> - int ret;
> + int retval, ret;
>
> ret = lwmi_om_notifier_call(&mode);
> if (ret)
> return ret;
>
> + /* If "no-mode" is the supported mode, ensure we never send current mode */
> + if (tunable_attr->cv_mode_id == LWMI_GZ_THERMAL_MODE_NONE)
> + mode = tunable_attr->cv_mode_id;
> +
> args.arg0 = LWMI_ATTR_ID(tunable_attr->device_id, tunable_attr->feature_id,
> mode, tunable_attr->type_id);
>
> @@ -847,6 +853,85 @@ static ssize_t attr_current_value_show(struct kobject *kobj,
> return sysfs_emit(buf, "%d\n", retval);
> }
>
> +/**
> + * lwmi_attr_01_is_supported() - Determine if the given attribute is supported.
> + * @tunable_attr: The attribute to verify.
> + *
> + * First check if the attribute has a corresponding capdata01 table in the cd01
> + * module under the "custom" mode (0xff). If that is not present then check if
> + * there is a corresponding "no-mode" (0x00) entry. If either of those passes,
> + * check capdata->supported for values > 0. If capdata is available, attempt to
> + * determine the set/get mode for the current value property using a similar
> + * pattern. If the value returned by either custom or no-mode is 0, or we get
> + * an error, we assume that mode is not supported. If any of the above checks
> + * fail then the attribute is not fully supported.
> + *
> + * The probed cd_mode_id/cv_mode_id are stored on the tunable_attr for later
> + * reference.
> + *
> + * Return: Support level, or an error code.
> + */
> +static int lwmi_attr_01_is_supported(struct tunable_attr_01 *tunable_attr)
> +{
> + struct lwmi_om_priv *priv = dev_get_drvdata(tunable_attr->dev);
> + u8 mode = LWMI_GZ_THERMAL_MODE_CUSTOM;
> + struct wmi_method_args_32 args;
> + struct capdata01 capdata;
> + int retval, ret;
> +
> + /* Determine tunable_attr->cd_mode_id */
> +no_mode_fallback_1:
> + args.arg0 = LWMI_ATTR_ID(tunable_attr->device_id, tunable_attr->feature_id,
> + mode, tunable_attr->type_id);
> +
> + ret = lwmi_cd01_get_data(priv->cd01_list, args.arg0, &capdata);
> + if (ret && mode) {
> + dev_dbg(tunable_attr->dev, "Attribute id %x not supported\n", args.arg0);

Add include.

> + mode = LWMI_GZ_THERMAL_MODE_NONE;
> + goto no_mode_fallback_1;

Is it possible to make a helper so you don't need these back gotos?

> + }
> + if (ret)
> + goto not_supported;
> + if (!capdata.supported) {
> + ret = -EOPNOTSUPP;
> + goto not_supported;
> + }
> +
> + tunable_attr->cd_mode_id = mode;
> +
> + /* Determine tunable_attr->cv_mode_id */
> + mode = LWMI_GZ_THERMAL_MODE_CUSTOM;
> +no_mode_fallback_2:
> + args.arg0 = LWMI_ATTR_ID(tunable_attr->device_id, tunable_attr->feature_id,
> + mode, tunable_attr->type_id);
> +
> + ret = lwmi_dev_evaluate_int(priv->wdev, 0x0, LWMI_FEATURE_VALUE_GET,
> + (unsigned char *)&args, sizeof(args),
> + &retval);
> + if ((ret && mode) || (!retval && mode)) {
> + dev_dbg(tunable_attr->dev, "Attribute id %x not supported\n", args.arg0);
> + mode = LWMI_GZ_THERMAL_MODE_NONE;
> + goto no_mode_fallback_2;

Same question here?

> + }
> + if (ret)
> + goto not_supported;
> + if (retval == 0) {
> + ret = -EOPNOTSUPP;
> + goto not_supported;
> + }
> +
> + tunable_attr->cv_mode_id = mode;
> + dev_dbg(tunable_attr->dev, "cd_mode_id: %02x%02x%02x%02x, cv_mode_id: %#08x attribute support level: %x\n",
> + tunable_attr->device_id, tunable_attr->feature_id, tunable_attr->cd_mode_id,
> + tunable_attr->type_id, args.arg0, capdata.supported);
> +
> + return capdata.supported;
> +
> +not_supported:
> + dev_dbg(tunable_attr->dev, "Attribute id %x not supported\n", args.arg0);
> + return ret;
> +}
> +
> /* Lenovo WMI Other Mode Attribute macros */
> #define __LWMI_ATTR_RO(_func, _name) \
> { \
> @@ -970,19 +1055,21 @@ static int lwmi_om_fw_attr_add(struct lwmi_om_priv *priv)
> }
>
> for (i = 0; i < ARRAY_SIZE(cd01_attr_groups) - 1; i++) {
> - err = sysfs_create_group(&priv->fw_attr_kset->kobj,
> - cd01_attr_groups[i].attr_group);
> - if (err)
> - goto err_remove_groups;
> -
> cd01_attr_groups[i].tunable_attr->dev = &priv->wdev->dev;
> + if (lwmi_attr_01_is_supported(cd01_attr_groups[i].tunable_attr) > 0) {

Reverse logic and use continue.

> + err = sysfs_create_group(&priv->fw_attr_kset->kobj,
> + cd01_attr_groups[i].attr_group);
> + if (err)
> + goto err_remove_groups;
> + }
> }
> return 0;
>
> err_remove_groups:
> while (i--)
> - sysfs_remove_group(&priv->fw_attr_kset->kobj,
> - cd01_attr_groups[i].attr_group);
> + if (lwmi_attr_01_is_supported(cd01_attr_groups[i].tunable_attr) > 0)

Reverse logic + continue.

> + sysfs_remove_group(&priv->fw_attr_kset->kobj,
> + cd01_attr_groups[i].attr_group);

You need to add braces for multiline constructs.

>
> kset_unregister(priv->fw_attr_kset);
>
>

--
i.