Re: [PATCH v3 3/4] HID: asus: Add WMI communication infrastructure

[Mario Limonciello <superm1@kernel.org>]

On 1/7/26 9:22 AM, Ionut Nechita (Sunlight Linux) wrote:
> From: Ionut Nechita <ionut_n2001@yahoo.com>
> 
> Add infrastructure for the HID driver to communicate with the asus-wmi
> driver for handling special keys that require WMI communication.
> 
> This includes:
> - Define ASUS_WMI_METHODID_NOTIF method ID in asus-wmi.h
> - Implement asus_wmi_send_event() function with proper conditional
>    compilation guards for when asus-wmi is not available
> 
> Reviewed-by: Denis Benato <benato.denis96@gmail.com>
> Signed-off-by: Ionut Nechita <ionut_n2001@yahoo.com>
> ---
>   drivers/hid/hid-asus.c                     | 31 ++++++++++++++++++++++
>   include/linux/platform_data/x86/asus-wmi.h |  1 +
>   2 files changed, 32 insertions(+)
> 
> diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
> index 15c24d5812763..8828a3b3054fa 100644
> --- a/drivers/hid/hid-asus.c
> +++ b/drivers/hid/hid-asus.c
> @@ -23,6 +23,7 @@
>   /*
>    */
>   
> +#include <linux/acpi.h>
>   #include <linux/dmi.h>
>   #include <linux/hid.h>
>   #include <linux/module.h>
> @@ -321,6 +322,36 @@ static int asus_e1239t_event(struct asus_drvdata *drvdat, u8 *data, int size)
>   	return 0;
>   }
>   
> +/*
> + * Send events to asus-wmi driver for handling special keys
> + */
> +#if IS_REACHABLE(CONFIG_ASUS_WMI)
I think this specific IS_REACHABLE isn't needed.

asus_wmi_evaluate_method() will return -ENODEV in that case already.

I think the warning you have below is actually helpful too because it 
will be obvious to a user they forgot to enable asus-wmi in their kernel 
config.

> +static int asus_wmi_send_event(struct asus_drvdata *drvdata, u8 code)
> +{
> +	int err;
> +	u32 retval;
> +
> +	err = asus_wmi_evaluate_method(ASUS_WMI_METHODID_DEVS,
> +				       ASUS_WMI_METHODID_NOTIF, code, &retval);
> +	if (err) {
> +		pr_warn("Failed to notify asus-wmi: %d\n", err);
> +		return err;
> +	}
> +
> +	if (retval != 0) {
> +		pr_warn("Failed to notify asus-wmi (retval): 0x%x\n", retval);
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +#else
> +static inline int asus_wmi_send_event(struct asus_drvdata *drvdata, u8 code)
> +{
> +	return -ENODEV;
> +}
> +#endif
> +
>   static int asus_event(struct hid_device *hdev, struct hid_field *field,
>   		      struct hid_usage *usage, __s32 value)
>   {
> diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> index 419491d4abca1..516538b5a527e 100644
> --- a/include/linux/platform_data/x86/asus-wmi.h
> +++ b/include/linux/platform_data/x86/asus-wmi.h
> @@ -29,6 +29,7 @@
>   #define ASUS_WMI_METHODID_KBFT		0x5446424B /* KeyBoard FilTer */
>   #define ASUS_WMI_METHODID_INIT		0x54494E49 /* INITialize */
>   #define ASUS_WMI_METHODID_HKEY		0x59454B48 /* Hot KEY ?? */
> +#define ASUS_WMI_METHODID_NOTIF		0x00100021 /* Notify method */
>   
>   #define ASUS_WMI_UNSUPPORTED_METHOD	0xFFFFFFFE
>