Re: [PATCH 0/9] platform/x86: lenovo-wmi-{other,capdata,helpers}: Improve robustness on buggy firmware

[Rong Zhang]

Hi Navon,

Thanks a lot for your test. 


于 2026年9月27日 GMT+08:00 05:04:15，Navon John Lukose <navonjohnlukose@xxxxxxxxx> 写道：
> Tested on a Yoga Pro 7 14IAH10 (83KF, BIOS QGCN35WW). Neither mainline
> nor the series binds here. This firmware has no
> LENOVO_CAPABILITY_DATA_01 in _WDG at all, so no component ever
> registers for that match and lwmi_om_master_bind() never runs. Skipping
> the match for GUIDs the firmware doesn't declare fixes it:
> 
> diff --git a/drivers/platform/x86/lenovo/wmi-capdata.c b/drivers/platform/x86/lenovo/wmi-capdata.c
> index 805e36ef7..d64520be1 100644
> --- a/drivers/platform/x86/lenovo/wmi-capdata.c
> +++ b/drivers/platform/x86/lenovo/wmi-capdata.c
> @@ -76,11 +76,13 @@ enum lwmi_cd_type {
>  #define LWMI_CD_TABLE_ITEM(_type)		\
>  	[_type] = {				\
>  		.name = #_type,			\
> +		.guid = _type##_GUID,		\
>  		.type = _type,			\
>  	}
>  
>  static const struct lwmi_cd_info {
>  	const char *name;
> +	const char *guid;
>  	enum lwmi_cd_type type;
>  } lwmi_cd_table[] = {
>  	LWMI_CD_TABLE_ITEM(LENOVO_CAPABILITY_DATA_00),
> @@ -166,6 +168,14 @@ void lwmi_cd_match_add_all(struct device *master, struct component_match **match
>  		if (lwmi_cd_table[i].type == LENOVO_FAN_TEST_DATA)
>  			continue;
>  
> +		/*
> +		 * Some firmware does not declare every capdata GUID at all, in
> +		 * which case no component would ever register for it and the
> +		 * master could never bind.
> +		 */
> +		if (!wmi_has_guid(lwmi_cd_table[i].guid))
> +			continue;

This was exactly what I did in the earlier revision while I was introducing the support for capdata00 and capdata_fan.

The wmi_has_guid() approach was eventually replaced by the sub-component approach, because the use of the former is strongly discouraged.

In the next revision I am going to convert capdata01 into a sub-component, too. In this manner some heavy and complex work in the series will become needless and can be simplified. While the sub-component approach itself is complex, we've had the infrastructure to make it work. Therefore wiring it up should be a trivial work.

Mark, Derek,

Do you know if there is any way to determine the existence of capdata01 using capdata00? 

> +
>  		component_match_add(master, matchptr, lwmi_cd_match,
>  				    (void *)&lwmi_cd_table[i].type);
>  		if (IS_ERR(*matchptr))
> diff --git a/drivers/platform/x86/lenovo/wmi-other.c b/drivers/platform/x86/lenovo/wmi-other.c
> index e6c8f6bcf..b196e9926 100644
> --- a/drivers/platform/x86/lenovo/wmi-other.c
> +++ b/drivers/platform/x86/lenovo/wmi-other.c
> @@ -1704,6 +1704,8 @@ static int lwmi_other_probe(struct wmi_device *wdev, const void *context)
>  	lwmi_cd_match_add_all(&wdev->dev, &master_match);
>  	if (IS_ERR(master_match))
>  		return PTR_ERR(master_match);
> +	if (!master_match)
> +		return -ENODEV;
>  
>  	return component_master_add_with_match(&wdev->dev, &lwmi_om_master_ops,
>  					       master_match);
> 
> With that on top (built out of tree against 7.2.5), lenovo_wmi_other
> binds and exposes fan1 and fan4 (min 1500/1800, max 5100/5400, input
> matching the EC tach fields). fanX_target pins both fans, 0 hands them
> back to the firmware curve, and out-of-range writes get -EINVAL. With
> the change above:
> 
> Tested-by: Navon John Lukose <navonjohnlukose@xxxxxxxxx>

Good to know fan control works on your device.

Thanks,
Rong