Re: [PATCH v10 06/16] platform/x86: lenovo-wmi-other: Limit adding attributes to supported devices

[Rong Zhang]

Hi Derek,

On Thu, 2026-04-30 at 07:56 -0700, Derek J. Clark wrote:
> On April 30, 2026 7:01:55 AM PDT, "Ilpo Järvinen" <ilpo.jarvinen@xxxxxxxxxxxxxxx> wrote:
> > On Sun, 12 Apr 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).
> > > - 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.
> > > 
> > > Fixes: edc4b183b794 ("platform/x86: Add Lenovo Other Mode WMI Driver")
> > > Reported-by: Kurt Borja <kuurtb@xxxxxxxxx>
> > > Closes: https://lore.kernel.org/platform-driver-x86/DG60P3SHXR8H.3NSEHMZ6J7XRC@xxxxxxxxx/
> > > Cc: stable@xxxxxxxxxxxxxxx
> > > Reviewed-by: Rong Zhang <i@xxxxxxxx>
> > > Tested-by: Rong Zhang <i@xxxxxxxx>
> > > Reviewed-by: Mark Pearson <mpearson-lenovo@xxxxxxxxx>
> > > Signed-off-by: Derek J. Clark <derekjohn.clark@xxxxxxxxx>
> > > ---
> > > v7:
> > >   - Move earlier in the series. This required dropping the use of
> > >     lwmi_attr_id as it will be added later.
> > >   - Add missing switch between cd_mode_id and cv_mode_id in
> > >     current_value_store.
> > > v6:
> > >   - Zero initialize args in lwmi_is_attr_01_supported.
> > >   - Fix formatting.
> > > v5:
> > >   - Move cv/cd_mode_id refrences from path 3/4.
> > >   - Add missing import for ARRAY_SIZE.
> > >   - Make lwmi_is_attr_01_supported return bool instead of u32.
> > >   - Various formatting fixes.
> > > v4:
> > >   - Use for loop instead of backtrace gotos for checking if an attribute
> > >     is supported.
> > >   - Add include for dev_printk.
> > >   - Wrap dev_dbg in lwmi_is_attr_01_supported earlier.
> > >   - Don't use symmetric cleanup of attributes in error states.
> > > ---
> > >  drivers/platform/x86/lenovo/wmi-gamezone.h |   1 +
> > >  drivers/platform/x86/lenovo/wmi-other.c    | 114 ++++++++++++++++++---
> > >  2 files changed, 98 insertions(+), 17 deletions(-)
> > > 
> > > diff --git a/drivers/platform/x86/lenovo/wmi-gamezone.h b/drivers/platform/x86/lenovo/wmi-gamezone.h
> > > index 6b163a5eeb95..ddb919cf6c36 100644
> > > --- a/drivers/platform/x86/lenovo/wmi-gamezone.h
> > > +++ b/drivers/platform/x86/lenovo/wmi-gamezone.h
> > > @@ -10,6 +10,7 @@ enum gamezone_events_type {
> > >  };
> > >  
> > >  enum thermal_mode {
> > > +	LWMI_GZ_THERMAL_MODE_NONE =	   0x00,
> > >  	LWMI_GZ_THERMAL_MODE_QUIET =	   0x01,
> > >  	LWMI_GZ_THERMAL_MODE_BALANCED =	   0x02,
> > >  	LWMI_GZ_THERMAL_MODE_PERFORMANCE = 0x03,
> > > diff --git a/drivers/platform/x86/lenovo/wmi-other.c b/drivers/platform/x86/lenovo/wmi-other.c
> > > index 50a03f5fd6ab..29d062a1c6dc 100644
> > > --- a/drivers/platform/x86/lenovo/wmi-other.c
> > > +++ b/drivers/platform/x86/lenovo/wmi-other.c
> > > @@ -550,6 +550,8 @@ struct tunable_attr_01 {
> > >  	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 = {
> > > @@ -775,7 +777,6 @@ static ssize_t attr_current_value_store(struct kobject *kobj,
> > >  	struct wmi_method_args_32 args = {};
> > >  	struct capdata01 capdata;
> > >  	enum thermal_mode mode;
> > > -	u32 attribute_id;
> > >  	u32 value;
> > >  	int ret;
> > >  
> > > @@ -786,13 +787,12 @@ static ssize_t attr_current_value_store(struct kobject *kobj,
> > >  	if (mode != LWMI_GZ_THERMAL_MODE_CUSTOM)
> > >  		return -EBUSY;
> > >  
> > > -	attribute_id =
> > > -		FIELD_PREP(LWMI_ATTR_DEV_ID_MASK, tunable_attr->device_id) |
> > > -		FIELD_PREP(LWMI_ATTR_FEAT_ID_MASK, tunable_attr->feature_id) |
> > > -		FIELD_PREP(LWMI_ATTR_MODE_ID_MASK, mode) |
> > > -		FIELD_PREP(LWMI_ATTR_TYPE_ID_MASK, tunable_attr->type_id);
> > > +	args.arg0 = FIELD_PREP(LWMI_ATTR_DEV_ID_MASK, tunable_attr->device_id) |
> > > +		    FIELD_PREP(LWMI_ATTR_FEAT_ID_MASK, tunable_attr->feature_id) |
> > > +		    FIELD_PREP(LWMI_ATTR_MODE_ID_MASK, tunable_attr->cd_mode_id) |
> > > +		    FIELD_PREP(LWMI_ATTR_TYPE_ID_MASK, tunable_attr->type_id);
> > >  
> > > -	ret = lwmi_cd01_get_data(priv->cd01_list, attribute_id, &capdata);
> > > +	ret = lwmi_cd01_get_data(priv->cd01_list, args.arg0, &capdata);
> > >  	if (ret)
> > >  		return ret;
> > >  
> > > @@ -803,7 +803,10 @@ static ssize_t attr_current_value_store(struct kobject *kobj,
> > >  	if (value < capdata.min_value || value > capdata.max_value)
> > >  		return -EINVAL;
> > >  
> > > -	args.arg0 = attribute_id;
> > > +	args.arg0 = FIELD_PREP(LWMI_ATTR_DEV_ID_MASK, tunable_attr->device_id) |
> > > +		    FIELD_PREP(LWMI_ATTR_FEAT_ID_MASK, tunable_attr->feature_id) |
> > > +		    FIELD_PREP(LWMI_ATTR_MODE_ID_MASK, tunable_attr->cv_mode_id) |
> > > +		    FIELD_PREP(LWMI_ATTR_TYPE_ID_MASK, tunable_attr->type_id);
> > 
> > It's already repeated a few times and you're adding more in this patch.
> > 
> > We should have a helper function for this encoding as it seems to 
> > repeat. That is, something that takes tunable_attr and mode as input
> > (the conversion of existing entries should be in own patch preceeding 
> > this fix patch).
> > 
> 
> Hi Ilpo,
> 
> A function for that is added in patch 10, though it is slightly modified from that to be more flexible is tunable_attr isn't used (such as with the fan test attributes)
> 
> Originally I had that patch preceding any additions, but after discussing with Rong we felt like it would be easier for stable backports if all the fixes were upfront. I can certainly move it back if you still prefer.

Moving it back is OK for me, too.

I think exposing non-fully-functioning fw-attrs on stable/LTS kernels
should be acceptable as long as reading/writing these attributes doesn't
break anything, which is exactly the case now (i.e., without this
patch).

Thanks a lot for your hard work in this series,
Rong

> 
> Thanks,
> Derek
> 
> 
> > >  	args.arg1 = value;
> > >  
> > >  	ret = lwmi_dev_evaluate_int(priv->wdev, 0x0, LWMI_FEATURE_VALUE_SET,
> > > @@ -837,7 +840,6 @@ 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;
> > > -	u32 attribute_id;
> > >  	int retval;
> > >  	int ret;
> > >  
> > > @@ -845,13 +847,14 @@ static ssize_t attr_current_value_show(struct kobject *kobj,
> > >  	if (ret)
> > >  		return ret;
> > >  
> > > -	attribute_id =
> > > -		FIELD_PREP(LWMI_ATTR_DEV_ID_MASK, tunable_attr->device_id) |
> > > -		FIELD_PREP(LWMI_ATTR_FEAT_ID_MASK, tunable_attr->feature_id) |
> > > -		FIELD_PREP(LWMI_ATTR_MODE_ID_MASK, mode) |
> > > -		FIELD_PREP(LWMI_ATTR_TYPE_ID_MASK, tunable_attr->type_id);
> > > +	/* 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 = attribute_id;
> > > +	args.arg0 = FIELD_PREP(LWMI_ATTR_DEV_ID_MASK, tunable_attr->device_id) |
> > > +		    FIELD_PREP(LWMI_ATTR_FEAT_ID_MASK, tunable_attr->feature_id) |
> > > +		    FIELD_PREP(LWMI_ATTR_MODE_ID_MASK, mode) |
> > > +		    FIELD_PREP(LWMI_ATTR_TYPE_ID_MASK, tunable_attr->type_id);
> > >  
> > >  	ret = lwmi_dev_evaluate_int(priv->wdev, 0x0, LWMI_FEATURE_VALUE_GET,
> > >  				    (unsigned char *)&args, sizeof(args),
> > > @@ -862,6 +865,81 @@ 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: bool.
> > > + */
> > > +static bool lwmi_attr_01_is_supported(struct tunable_attr_01 *tunable_attr)
> > > +{
> > > +	u8 modes[2] = { LWMI_GZ_THERMAL_MODE_CUSTOM, LWMI_GZ_THERMAL_MODE_NONE };
> > > +	struct lwmi_om_priv *priv = dev_get_drvdata(tunable_attr->dev);
> > > +	struct wmi_method_args_32 args = {};
> > > +	bool cd_mode_found = false;
> > > +	bool cv_mode_found = false;
> > > +	struct capdata01 capdata;
> > > +	int retval, ret, i;
> > > +
> > > +	/* Determine tunable_attr->cd_mode_id*/
> > > +	for (i = 0; i < ARRAY_SIZE(modes); i++) {
> > > +		args.arg0 = FIELD_PREP(LWMI_ATTR_DEV_ID_MASK, tunable_attr->device_id) |
> > > +			    FIELD_PREP(LWMI_ATTR_FEAT_ID_MASK, tunable_attr->feature_id) |
> > > +			    FIELD_PREP(LWMI_ATTR_MODE_ID_MASK, modes[i]) |
> > > +			    FIELD_PREP(LWMI_ATTR_TYPE_ID_MASK, tunable_attr->type_id);
> > > +
> > > +		ret = lwmi_cd01_get_data(priv->cd01_list, args.arg0, &capdata);
> > > +		if (ret || !capdata.supported)
> > > +			continue;
> > > +		tunable_attr->cd_mode_id = modes[i];
> > > +		cd_mode_found = true;
> > > +		break;
> > > +	}
> > > +
> > > +	if (!cd_mode_found)
> > > +		return cd_mode_found;
> > > +
> > > +	dev_dbg(tunable_attr->dev,
> > > +		"cd_mode_id: %#010x\n", args.arg0);
> > > +
> > > +	/* Determine tunable_attr->cv_mode_id, returns 1 if supported*/
> > > +	for (i = 0; i < ARRAY_SIZE(modes); i++) {
> > > +		args.arg0 = FIELD_PREP(LWMI_ATTR_DEV_ID_MASK, tunable_attr->device_id) |
> > > +			    FIELD_PREP(LWMI_ATTR_FEAT_ID_MASK, tunable_attr->feature_id) |
> > > +			    FIELD_PREP(LWMI_ATTR_MODE_ID_MASK, modes[i]) |
> > > +			    FIELD_PREP(LWMI_ATTR_TYPE_ID_MASK, tunable_attr->type_id);
> > > +
> > > +		ret = lwmi_dev_evaluate_int(priv->wdev, 0x0, LWMI_FEATURE_VALUE_GET,
> > > +					    (unsigned char *)&args, sizeof(args),
> > > +					    &retval);
> > > +		if (ret || !retval)
> > > +			continue;
> > > +		tunable_attr->cv_mode_id = modes[i];
> > > +		cv_mode_found = true;
> > > +		break;
> > > +	}
> > > +
> > > +	if (!cv_mode_found)
> > > +		return cv_mode_found;
> > > +
> > > +	dev_dbg(tunable_attr->dev, "cv_mode_id: %#010x, attribute support level: %#010x\n",
> > > +		args.arg0, capdata.supported);
> > > +
> > > +	return capdata.supported > 0 ? true : false;
> > > +}
> > > +
> > >  /* Lenovo WMI Other Mode Attribute macros */
> > >  #define __LWMI_ATTR_RO(_func, _name)                                  \
> > >  	{                                                             \
> > > @@ -985,12 +1063,14 @@ static void lwmi_om_fw_attr_add(struct lwmi_om_priv *priv)
> > >  	}
> > >  
> > >  	for (i = 0; i < ARRAY_SIZE(cd01_attr_groups) - 1; i++) {
> > > +		cd01_attr_groups[i].tunable_attr->dev = &priv->wdev->dev;
> > > +		if (!lwmi_attr_01_is_supported(cd01_attr_groups[i].tunable_attr))
> > > +			continue;
> > > +
> > >  		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;
> > >  	}
> > >  	return;
> > >  
> > > 
> >