Re: [PATCH v3 6/6] platform/x86: lenovo-wmi-other: Add WMI battery charge limiting.

[Rong Zhang]

Hi Derek,

On Wed, 2026-02-25 at 10:23 -0800, Derek J. Clark wrote:
> On February 25, 2026 9:55:40 AM PST, Rong Zhang <i@xxxxxxxx> wrote:
> > Hi Derek,
> > 
> > There is an extra dot (period) in the title. Please remove it.
> > 
> > On Tue, 2026-02-24 at 04:32 +0000, Derek J. Clark wrote:
> > > Add charge-type power supply extension for devices that support WMI based
> > > charge enable/disable. Lenovo Legion devices that implement function ID
> > > and capdata 00 ID 0x03010001 are able to enable or disable charging
> > > through the lenovo-wmi-other interface.
> > 
> > "disable charging"...
> > 
> > I'd expect it pauses charging immediately and unconditionally instead
> > of setting a threshold, especially considering the its name
> > "INSTANT_MODE". If this is the case, I don't think it fits the
> > definition of POWER_SUPPLY_CHARGE_TYPE_LONGLIFE. It'd better to use
> > POWER_SUPPLY_CHARGE_TYPE_NONE.
> 
> It really just sets a charge threshold of 80% and lowers the charge speed a bit. I'll come up with a better name than the one Lenovo uses in their docs.

Makes sense. Thanks for clarification.

FYI, ideapad-laptop conservative mode (i.e.,
POWER_SUPPLY_CHARGE_TYPE_LONGLIFE) doesn't lower the charge speed. It's
just a trivial divergence and isn't a blocker of using
POWER_SUPPLY_CHARGE_TYPE_LONGLIFE here of course.

Thanks,
Rong

> > > The ideapad_laptop driver
> > > conflicts with this if it can also provide the attribute, so we have to
> > > get the acpi_handle and check for the same ACPI methods that enable the
> > > feature in that driver. The ACPI method is more reliable from my testing
> > > when both are present, so there is no need to modify the ideapad_laptop
> > > driver instead.
> > 
> > When ideapad-laptop is blacklisted, there should be no conflict. I
> > would suggest adding a module parameter to force wmi-other to register
> > psy_ext anyway so that users can have their own choice.
> > 
> 
> That should be fine. I've found the WMI interface is a little buggy on devices that support the ACPI method. I.e. on the Go S and Go 2 it always reports the "Enabled" status, but changing it shows the ACPI method reporting the correct value. (I used a different attr name to test this)
> 
> > > Reviewed-by: Mark Pearson <mpearson-lenovo@xxxxxxxxx>
> > > Signed-off-by: Derek J. Clark <derekjohn.clark@xxxxxxxxx>
> > > ---
> > >  drivers/platform/x86/lenovo/wmi-capdata.h |   1 +
> > >  drivers/platform/x86/lenovo/wmi-other.c   | 230 ++++++++++++++++++++++
> > >  2 files changed, 231 insertions(+)
> > > 
> > > diff --git a/drivers/platform/x86/lenovo/wmi-capdata.h b/drivers/platform/x86/lenovo/wmi-capdata.h
> > > index b7f9ee7b301a..00471551e7d6 100644
> > > --- a/drivers/platform/x86/lenovo/wmi-capdata.h
> > > +++ b/drivers/platform/x86/lenovo/wmi-capdata.h
> > > @@ -26,6 +26,7 @@
> > >  enum lwmi_device_id {
> > >  	LWMI_DEVICE_ID_CPU = 0x01,
> > >  	LWMI_DEVICE_ID_GPU = 0x02,
> > > +	LWMI_DEVICE_ID_PSU = 0x03,
> > >  	LWMI_DEVICE_ID_FAN = 0x04,
> > >  };
> > >  
> > > diff --git a/drivers/platform/x86/lenovo/wmi-other.c b/drivers/platform/x86/lenovo/wmi-other.c
> > > index 7f0d5a17b44f..b2daff1b45c2 100644
> > > --- a/drivers/platform/x86/lenovo/wmi-other.c
> > > +++ b/drivers/platform/x86/lenovo/wmi-other.c
> > > @@ -42,9 +42,12 @@
> > >  #include <linux/module.h>
> > >  #include <linux/notifier.h>
> > >  #include <linux/platform_profile.h>
> > > +#include <linux/power_supply.h>
> > >  #include <linux/types.h>
> > >  #include <linux/wmi.h>
> > >  
> > > +#include <acpi/battery.h>
> > > +
> > >  #include "wmi-capdata.h"
> > >  #include "wmi-events.h"
> > >  #include "wmi-gamezone.h"
> > > @@ -78,10 +81,17 @@ enum lwmi_feature_id_gpu {
> > >  	LWMI_FEATURE_ID_GPU_NV_CPU_BOOST = 0x0b,
> > >  };
> > >  
> > > +enum lwmi_feature_id_psu {
> > > +	LWMI_FEATURE_ID_PSU_INSTANT_MODE = 0x01,
> > > +	LWMI_FEATURE_ID_PSU_CHARGE_MODE = 0x02,
> > 
> > I see no code referencing LWMI_FEATURE_ID_PSU_CHARGE_MODE. What's the
> > mode for?
> 
> It's another option exposed by some BIOS that is supposed to have similar functionality. None of my devices support it properly so I removed it but forgot to clean up this define.
> 
> > > +};
> > > +
> > >  #define LWMI_FEATURE_ID_FAN_RPM 0x03
> > >  
> > >  #define LWMI_TYPE_ID_NONE 0x00
> > >  #define LWMI_TYPE_ID_CROSSLOAD 0x01
> > > +#define LWMI_TYPE_ID_PSU_AC 0x01
> > > +#define LWMI_TYPE_ID_PSU_PD 0x02
> > >  
> > >  #define LWMI_FEATURE_VALUE_GET 17
> > >  #define LWMI_FEATURE_VALUE_SET 18
> > > @@ -92,10 +102,17 @@ enum lwmi_feature_id_gpu {
> > >  
> > >  #define LWMI_FAN_DIV 100
> > >  
> > > +#define LWMI_CHARGE_MODE_ENABLED	0x00
> > > +#define LWMI_CHARGE_MODE_DISABLED	0x01
> > > +
> > >  #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))
> > >  
> > > +#define LWMI_ATTR_ID_PSU(feat, type)		\
> > > +	LWMI_ATTR_ID(LWMI_DEVICE_ID_PSU, feat,		\
> > > +		     LWMI_GZ_THERMAL_MODE_NONE, type)
> > > +
> > 
> > Unaligned backslashes.
> > 
> > >  #define LWMI_OM_SYSFS_NAME "lenovo-wmi-other"
> > >  #define LWMI_OM_HWMON_NAME "lenovo_wmi_other"
> > >  
> > > @@ -137,6 +154,8 @@ struct lwmi_om_priv {
> > >  		bool capdata00_collected : 1;
> > >  		bool capdata_fan_collected : 1;
> > >  	} fan_flags;
> > > +
> > > +	struct acpi_battery_hook battery_hook;
> > >  };
> > >  
> > >  /*
> > > @@ -561,6 +580,216 @@ static void lwmi_om_fan_info_collect_cd_fan(struct device *dev, struct cd_list *
> > >  	lwmi_om_hwmon_add(priv);
> > >  }
> > >  
> > > +/* ======== Power Supply Extension (component: lenovo-wmi-capdata 00) ======== */
> > > +
> > > +/**
> > > + * lwmi_psy_ext_get_prop() - Get a power_supply_ext property
> > > + * @ps: The battery that was extended
> > > + * @ext: The extension
> > > + * @ext_data: Pointer the lwmi_om_priv drvdata
> > > + * @prop: The property to read
> > > + * @val: The value to return
> > > + *
> > > + * Writes the given value to the power_supply_ext property
> > > + *
> > > + * Return: 0 on success, or an error
> > > + */
> > > +static int lwmi_psy_ext_get_prop(struct power_supply *ps,
> > > +				 const struct power_supply_ext *ext,
> > > +				 void *ext_data,
> > > +				 enum power_supply_property prop,
> > > +				 union power_supply_propval *val)
> > > +{
> > > +	struct lwmi_om_priv *priv = ext_data;
> > > +	struct wmi_method_args_32 args;
> > > +	u32 retval;
> > > +	int ret;
> > > +
> > > +	args.arg0 = LWMI_ATTR_ID_PSU(LWMI_FEATURE_ID_PSU_INSTANT_MODE, LWMI_TYPE_ID_PSU_AC);
> > > +
> > > +	ret = lwmi_dev_evaluate_int(priv->wdev, 0x0, LWMI_FEATURE_VALUE_GET,
> > > +				    (unsigned char *)&args, sizeof(args),
> > > +				    &retval);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	dev_dbg(&priv->wdev->dev, "Got return value %x for property %x\n", retval, prop);
> > > +
> > > +	if (retval == LWMI_CHARGE_MODE_DISABLED)
> > > +		val->intval = POWER_SUPPLY_CHARGE_TYPE_LONGLIFE;
> > > +	else
> > > +		val->intval = POWER_SUPPLY_CHARGE_TYPE_STANDARD;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * lwmi_psy_ext_set_prop() - Set a power_supply_ext property
> > > + * @ps: The battery that was extended
> > > + * @ext: The extension
> > > + * @ext_data: Pointer the lwmi_om_priv drvdata
> > > + * @prop: The property to write
> > > + * @val: The value to write
> > > + *
> > > + * Writes the given value to the power_supply_ext property
> > > + *
> > > + * Return: 0 on success, or an error
> > > + */
> > > +static int lwmi_psy_ext_set_prop(struct power_supply *ps,
> > > +				 const struct power_supply_ext *ext,
> > > +				 void *ext_data,
> > > +				 enum power_supply_property prop,
> > > +				 const union power_supply_propval *val)
> > > +{
> > > +	struct lwmi_om_priv *priv = ext_data;
> > > +	struct wmi_method_args_32 args;
> > > +
> > > +	args.arg0 = LWMI_ATTR_ID_PSU(LWMI_FEATURE_ID_PSU_INSTANT_MODE, LWMI_TYPE_ID_PSU_AC);
> > > +	if (val->intval == POWER_SUPPLY_CHARGE_TYPE_LONGLIFE)
> > > +		args.arg1 = LWMI_CHARGE_MODE_DISABLED;
> > > +	else
> > > +		args.arg1 = LWMI_CHARGE_MODE_ENABLED;
> > > +
> > > +	dev_dbg(&priv->wdev->dev, "Attempting to set %#08x for property %x to %x\n",
> > > +		args.arg0, prop, args.arg1);
> > > +
> > > +	return lwmi_dev_evaluate_int(priv->wdev, 0x0, LWMI_FEATURE_VALUE_SET,
> > > +				     (unsigned char *)&args, sizeof(args), NULL);
> > > +}
> > > +
> > > +/**
> > > + * lwmi_psy_prop_is_writeable() - Determine if the property is supported
> > > + * @ps: The battery that was extended
> > > + * @ext: The extension
> > > + * @ext_data: Pointer the lwmi_om_priv drvdata
> > > + * @prop: The property to check
> > > + *
> > > + * Checks capdata 00 to determine if the property is supported.
> > > + *
> > > + * Return: Support level, or false
> > > + */
> > > +static int lwmi_psy_prop_is_writeable(struct power_supply *ps,
> > > +				      const struct power_supply_ext *ext,
> > > +				      void *ext_data,
> > > +				      enum power_supply_property prop)
> > > +{
> > > +	struct lwmi_om_priv *priv = ext_data;
> > > +	struct capdata00 capdata;
> > > +	u32 attribute_id = LWMI_ATTR_ID_PSU(LWMI_FEATURE_ID_PSU_INSTANT_MODE, LWMI_TYPE_ID_PSU_AC);
> > > +	int ret;
> > > +
> > > +	ret = lwmi_cd00_get_data(priv->cd00_list, attribute_id, &capdata);
> > > +	if (ret)
> > > +		return false;
> > > +
> > > +	dev_dbg(&priv->wdev->dev, "Battery charge mode (%#08x) support level: %x\n",
> > > +		attribute_id, capdata.supported);
> > > +
> > > +	return capdata.supported;
> > > +}
> > > +
> > > +static const enum power_supply_property lwmi_psy_ext_props[] = {
> > > +	POWER_SUPPLY_PROP_CHARGE_TYPES,
> > > +};
> > > +
> > > +static const struct power_supply_ext lwmi_psy_ext = {
> > > +	.name			= LWMI_OM_SYSFS_NAME,
> > > +	.properties		= lwmi_psy_ext_props,
> > > +	.num_properties		= ARRAY_SIZE(lwmi_psy_ext_props),
> > > +	.charge_types		= (BIT(POWER_SUPPLY_CHARGE_TYPE_STANDARD) |
> > > +				   BIT(POWER_SUPPLY_CHARGE_TYPE_LONGLIFE)),
> > > +	.get_property		= lwmi_psy_ext_get_prop,
> > > +	.set_property		= lwmi_psy_ext_set_prop,
> > > +	.property_is_writeable	= lwmi_psy_prop_is_writeable,
> > > +};
> > > +
> > > +/**
> > > + * lwmi_add_battery() - Connect the power_supply_ext
> > > + * @battery: The battery to extend
> > > + * @hook: The driver hook used to extend the battery
> > > + *
> > > + * Return: 0 on success, or an error.
> > > + */
> > > +static int lwmi_add_battery(struct power_supply *battery, struct acpi_battery_hook *hook)
> > > +{
> > > +	struct lwmi_om_priv *priv = container_of(hook, struct lwmi_om_priv, battery_hook);
> > > +
> > > +	return power_supply_register_extension(battery, &lwmi_psy_ext, &priv->wdev->dev, priv);
> > > +}
> > > +
> > > +/**
> > > + * lwmi_remove_battery() - Disconnect the power_supply_ext
> > > + * @battery: The battery that was extended
> > > + * @hook: The driver hook used to extend the battery
> > > + *
> > > + * Return: 0 on success, or an error.
> > > + */
> > > +static int lwmi_remove_battery(struct power_supply *battery, struct acpi_battery_hook *hook)
> > > +{
> > > +	power_supply_unregister_extension(battery, &lwmi_psy_ext);
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * lwmi_acpi_match() - Attempts to return the ideapad acpi handle
> > > + * @handle: The ACPI handle that manages battery charging
> > > + * @lvl: Unused
> > > + * @context: Void pointer to the acpi_handle object to return
> > > + * @retval: Unused
> > > + *
> > > + * Checks if the ideapad_laptop driver is going to manage charge_type first,
> > > + * then if not, hooks the battery to our WMI methods.
> > > + *
> > > + * Return: AE_CTRL_TERMINATE if found, AE_OK if not found.
> > > + */
> > > +static acpi_status lwmi_acpi_match(acpi_handle handle, u32 lvl,
> > > +				   void *context, void **retval)
> > > +{
> > > +	if (!handle)
> > > +		return AE_OK;
> > > +
> > > +	acpi_handle *ahand = context;
> > > +	*ahand = handle;
> > > +
> > > +	return AE_CTRL_TERMINATE;
> > > +}
> > > +
> > > +/**
> > > + * lwmi_om_ps_ext_init() - Hooks power supply extension to device battery
> > > + * @priv: Driver private data
> > > + *
> > > + * Checks if the ideapad_laptop driver is going to manage charge_type first,
> > > + * then if not, hooks the battery to our WMI methods.
> > > + */
> > > +static void lwmi_om_ps_ext_init(struct lwmi_om_priv *priv)
> > > +{
> > > +	static const char * const ideapad_hid = "VPC2004";
> > > +	acpi_handle handle = NULL;
> > > +	int ret;
> > > +
> > > +	/* Deconflict ideapad_laptop driver */
> > > +	ret = acpi_get_devices(ideapad_hid, lwmi_acpi_match, &handle, NULL);
> > > +	if (ret)
> > > +		return;
> > > +
> > > +	if (!handle)
> > > +		return;
> > 
> > I am a bit confused here. If VPC2004 is not found, handle should remain
> > NULL. In this case we have no conflict, right?
> > 
> > Thanks,
> > Rong
> > 
> > > +
> > > +	if (acpi_has_method(handle, "GBMD") && acpi_has_method(handle, "SBMC")) {
> > > +		dev_dbg(&priv->wdev->dev, "ideapad_laptop driver manages battery for device.\n");
> > > +		return;
> > > +	}
> > > +
> > > +	/* Add battery hooks */
> > > +	priv->battery_hook.add_battery	= lwmi_add_battery,
> > > +	priv->battery_hook.remove_battery	= lwmi_remove_battery,
> > > +	priv->battery_hook.name		= "Lenovo WMI Other Battery Extension",
> > > +
> > > +	ret = devm_battery_hook_register(&priv->wdev->dev, &priv->battery_hook);
> > > +	if (ret)
> > > +		dev_err(&priv->wdev->dev, "Error during battery hook: %i\n", ret);
> > > +}
> > > +
> > >  /* ======== fw_attributes (component: lenovo-wmi-capdata 01) ======== */
> > >  
> > >  struct tunable_attr_01 {
> > > @@ -1325,6 +1554,7 @@ static int lwmi_om_master_bind(struct device *dev)
> > >  		return -ENODEV;
> > >  
> > >  	lwmi_om_fan_info_collect_cd00(priv);
> > > +	lwmi_om_ps_ext_init(priv);
> > >  
> > >  	return lwmi_om_fw_attr_add(priv);
> > >  }