[PATCH v4] platform/x86: alienware-wmi-base: Transition to new WMI API

[PATCH v4] platform/x86: alienware-wmi-base: Transition to new WMI API

[Kurt Borja]

Transition to the new wmi_buffer based WMI API.

Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
v4:
  - Rebase to use the new wmidev_invoke_method() with size check

v3: https://patch.msgid.link/20260331-aw-new-api-v3-1-ef03b94529d8@gmail.com
  - Use __free() instead of manual cleanup.
  - Include <linux/types.h>

v2: https://patch.msgid.link/20260331-aw-new-api-v2-1-3b0d33bf8d22@gmail.com
  - Cast wmi_buffer data to __le32 and then use le32_to_cpu() before
    returning

v1: https://patch.msgid.link/20260330-aw-new-api-v1-1-95910bfa1b38@gmail.com
---
 drivers/platform/x86/dell/alienware-wmi-base.c | 31 ++++++++++++++++----------
 1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/drivers/platform/x86/dell/alienware-wmi-base.c b/drivers/platform/x86/dell/alienware-wmi-base.c
index 64562b92314f..21d3acfbd73d 100644
--- a/drivers/platform/x86/dell/alienware-wmi-base.c
+++ b/drivers/platform/x86/dell/alienware-wmi-base.c
@@ -12,8 +12,13 @@
 #include <linux/cleanup.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
 #include <linux/dmi.h>
 #include <linux/leds.h>
+
+#include <asm/byteorder.h>
+
 #include "alienware-wmi.h"
 
 MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");
@@ -150,21 +155,23 @@ u8 alienware_interface;
 int alienware_wmi_command(struct wmi_device *wdev, u32 method_id,
 			  void *in_args, size_t in_size, u32 *out_data)
 {
-	struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
-	struct acpi_buffer in = {in_size, in_args};
-	acpi_status ret;
+	struct wmi_buffer out, in = {
+		.data = in_args,
+		.length = in_size,
+	};
+	int ret;
 
-	ret = wmidev_evaluate_method(wdev, 0, method_id, &in, out_data ? &out : NULL);
-	if (ACPI_FAILURE(ret))
-		return -EIO;
-
-	union acpi_object *obj __free(kfree) = out.pointer;
+	if (out_data)
+		ret = wmidev_invoke_method(wdev, 0, method_id, &in, &out,
+					   sizeof(*out_data));
+	else
+		ret = wmidev_invoke_method(wdev, 0, method_id, &in, NULL, 0);
+	if (ret)
+		return ret;
 
 	if (out_data) {
-		if (obj && obj->type == ACPI_TYPE_INTEGER)
-			*out_data = (u32)obj->integer.value;
-		else
-			return -ENOMSG;
+		__le32 *data __free(kfree) = out.data;
+		*out_data = le32_to_cpu(*data);
 	}
 
 	return 0;

---
base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
change-id: 20260123-aw-new-api-1c18f1011f35

-- 
Thanks, 
 ~ Kurt

Re: [PATCH v4] platform/x86: alienware-wmi-base: Transition to new WMI API

[Armin Wolf]

Am 28.04.26 um 18:37 schrieb Kurt Borja:

> Transition to the new wmi_buffer based WMI API.
>
> Signed-off-by: Kurt Borja <kuurtb@gmail.com>
> ---
> v4:
>    - Rebase to use the new wmidev_invoke_method() with size check
>
> v3: https://patch.msgid.link/20260331-aw-new-api-v3-1-ef03b94529d8@gmail.com
>    - Use __free() instead of manual cleanup.
>    - Include <linux/types.h>
>
> v2: https://patch.msgid.link/20260331-aw-new-api-v2-1-3b0d33bf8d22@gmail.com
>    - Cast wmi_buffer data to __le32 and then use le32_to_cpu() before
>      returning
>
> v1: https://patch.msgid.link/20260330-aw-new-api-v1-1-95910bfa1b38@gmail.com
> ---
>   drivers/platform/x86/dell/alienware-wmi-base.c | 31 ++++++++++++++++----------
>   1 file changed, 19 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/platform/x86/dell/alienware-wmi-base.c b/drivers/platform/x86/dell/alienware-wmi-base.c
> index 64562b92314f..21d3acfbd73d 100644
> --- a/drivers/platform/x86/dell/alienware-wmi-base.c
> +++ b/drivers/platform/x86/dell/alienware-wmi-base.c
> @@ -12,8 +12,13 @@
>   #include <linux/cleanup.h>
>   #include <linux/module.h>
>   #include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
>   #include <linux/dmi.h>
>   #include <linux/leds.h>
> +
> +#include <asm/byteorder.h>
> +
>   #include "alienware-wmi.h"
>   
>   MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");
> @@ -150,21 +155,23 @@ u8 alienware_interface;
>   int alienware_wmi_command(struct wmi_device *wdev, u32 method_id,
>   			  void *in_args, size_t in_size, u32 *out_data)
>   {
> -	struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
> -	struct acpi_buffer in = {in_size, in_args};
> -	acpi_status ret;
> +	struct wmi_buffer out, in = {
> +		.data = in_args,
> +		.length = in_size,
> +	};
> +	int ret;
>   
> -	ret = wmidev_evaluate_method(wdev, 0, method_id, &in, out_data ? &out : NULL);
> -	if (ACPI_FAILURE(ret))
> -		return -EIO;
> -
> -	union acpi_object *obj __free(kfree) = out.pointer;
> +	if (out_data)
> +		ret = wmidev_invoke_method(wdev, 0, method_id, &in, &out,
> +					   sizeof(*out_data));
> +	else
> +		ret = wmidev_invoke_method(wdev, 0, method_id, &in, NULL, 0);
> +	if (ret)
> +		return ret;
>   
>   	if (out_data) {
> -		if (obj && obj->type == ACPI_TYPE_INTEGER)
> -			*out_data = (u32)obj->integer.value;
> -		else
> -			return -ENOMSG;
> +		__le32 *data __free(kfree) = out.data;
> +		*out_data = le32_to_cpu(*data);
>   	}

Hi,

calling wmidev_invoke_method() with a NULL output buffer will likely lead to crashes. This happens
because wmidev_invoke_method() demands that a valid pointer to a output buffer is provided by the
caller. I suggest that you use wmidev_invoke_procedure() instead:

	__le32 *data __free(kfree) = NULL;

	if (!out_data)
		return wmidev_invoke_procedure(wdev, 0, method_id, &in);

	ret = wmidev_invoke_method(wdev, 0, method_id, &in, &out, sizeof(*data));
	if (ret < 0)
		return ret;

	result = out.data
	...

Thanks,
Armin Wolf

>   
>   	return 0;
>
> ---
> base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
> change-id: 20260123-aw-new-api-1c18f1011f35
>

Re: [PATCH v4] platform/x86: alienware-wmi-base: Transition to new WMI API

[Kurt Borja]

On Tue Apr 28, 2026 at 2:27 PM -05, Armin Wolf wrote:
> Am 28.04.26 um 18:37 schrieb Kurt Borja:
>
>> Transition to the new wmi_buffer based WMI API.
>>
>> Signed-off-by: Kurt Borja <kuurtb@gmail.com>
>> ---
>> v4:
>>    - Rebase to use the new wmidev_invoke_method() with size check
>>
>> v3: https://patch.msgid.link/20260331-aw-new-api-v3-1-ef03b94529d8@gmail.com
>>    - Use __free() instead of manual cleanup.
>>    - Include <linux/types.h>
>>
>> v2: https://patch.msgid.link/20260331-aw-new-api-v2-1-3b0d33bf8d22@gmail.com
>>    - Cast wmi_buffer data to __le32 and then use le32_to_cpu() before
>>      returning
>>
>> v1: https://patch.msgid.link/20260330-aw-new-api-v1-1-95910bfa1b38@gmail.com
>> ---
>>   drivers/platform/x86/dell/alienware-wmi-base.c | 31 ++++++++++++++++----------
>>   1 file changed, 19 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/platform/x86/dell/alienware-wmi-base.c b/drivers/platform/x86/dell/alienware-wmi-base.c
>> index 64562b92314f..21d3acfbd73d 100644
>> --- a/drivers/platform/x86/dell/alienware-wmi-base.c
>> +++ b/drivers/platform/x86/dell/alienware-wmi-base.c
>> @@ -12,8 +12,13 @@
>>   #include <linux/cleanup.h>
>>   #include <linux/module.h>
>>   #include <linux/platform_device.h>
>> +#include <linux/slab.h>
>> +#include <linux/types.h>
>>   #include <linux/dmi.h>
>>   #include <linux/leds.h>
>> +
>> +#include <asm/byteorder.h>
>> +
>>   #include "alienware-wmi.h"
>>   
>>   MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");
>> @@ -150,21 +155,23 @@ u8 alienware_interface;
>>   int alienware_wmi_command(struct wmi_device *wdev, u32 method_id,
>>   			  void *in_args, size_t in_size, u32 *out_data)
>>   {
>> -	struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
>> -	struct acpi_buffer in = {in_size, in_args};
>> -	acpi_status ret;
>> +	struct wmi_buffer out, in = {
>> +		.data = in_args,
>> +		.length = in_size,
>> +	};
>> +	int ret;
>>   
>> -	ret = wmidev_evaluate_method(wdev, 0, method_id, &in, out_data ? &out : NULL);
>> -	if (ACPI_FAILURE(ret))
>> -		return -EIO;
>> -
>> -	union acpi_object *obj __free(kfree) = out.pointer;
>> +	if (out_data)
>> +		ret = wmidev_invoke_method(wdev, 0, method_id, &in, &out,
>> +					   sizeof(*out_data));
>> +	else
>> +		ret = wmidev_invoke_method(wdev, 0, method_id, &in, NULL, 0);
>> +	if (ret)
>> +		return ret;
>>   
>>   	if (out_data) {
>> -		if (obj && obj->type == ACPI_TYPE_INTEGER)
>> -			*out_data = (u32)obj->integer.value;
>> -		else
>> -			return -ENOMSG;
>> +		__le32 *data __free(kfree) = out.data;
>> +		*out_data = le32_to_cpu(*data);
>>   	}
>
> Hi,
>
> calling wmidev_invoke_method() with a NULL output buffer will likely lead to crashes. This happens
> because wmidev_invoke_method() demands that a valid pointer to a output buffer is provided by the
> caller. I suggest that you use wmidev_invoke_procedure() instead:
>
> 	__le32 *data __free(kfree) = NULL;
>
> 	if (!out_data)
> 		return wmidev_invoke_procedure(wdev, 0, method_id, &in);
>
> 	ret = wmidev_invoke_method(wdev, 0, method_id, &in, &out, sizeof(*data));
> 	if (ret < 0)
> 		return ret;
>
> 	result = out.data
> 	...

Hi Armin,

You're right, I thought the only difference between _procedure and
_method was the size check.

Also, Sashiko [1] reported that out.data might be ZERO_SIZE_PTR even if
wmidev_invoke_method() succeeds. I thought it was a false positive but I
looked further and it was actually a bug. I submitted a fix for this.

[1] https://sashiko.dev/#/patchset/20260428-aw-new-api-v4-1-d2c06241d7ad%40gmail.com

-- 
Thanks,
 ~ Kurt

Re: [PATCH v4] platform/x86: alienware-wmi-base: Transition to new WMI API

[Armin Wolf]

Am 29.04.26 um 15:23 schrieb Kurt Borja:

> On Tue Apr 28, 2026 at 2:27 PM -05, Armin Wolf wrote:
>> Am 28.04.26 um 18:37 schrieb Kurt Borja:
>>
>>> Transition to the new wmi_buffer based WMI API.
>>>
>>> Signed-off-by: Kurt Borja <kuurtb@gmail.com>
>>> ---
>>> v4:
>>>     - Rebase to use the new wmidev_invoke_method() with size check
>>>
>>> v3: https://patch.msgid.link/20260331-aw-new-api-v3-1-ef03b94529d8@gmail.com
>>>     - Use __free() instead of manual cleanup.
>>>     - Include <linux/types.h>
>>>
>>> v2: https://patch.msgid.link/20260331-aw-new-api-v2-1-3b0d33bf8d22@gmail.com
>>>     - Cast wmi_buffer data to __le32 and then use le32_to_cpu() before
>>>       returning
>>>
>>> v1: https://patch.msgid.link/20260330-aw-new-api-v1-1-95910bfa1b38@gmail.com
>>> ---
>>>    drivers/platform/x86/dell/alienware-wmi-base.c | 31 ++++++++++++++++----------
>>>    1 file changed, 19 insertions(+), 12 deletions(-)
>>>
>>> diff --git a/drivers/platform/x86/dell/alienware-wmi-base.c b/drivers/platform/x86/dell/alienware-wmi-base.c
>>> index 64562b92314f..21d3acfbd73d 100644
>>> --- a/drivers/platform/x86/dell/alienware-wmi-base.c
>>> +++ b/drivers/platform/x86/dell/alienware-wmi-base.c
>>> @@ -12,8 +12,13 @@
>>>    #include <linux/cleanup.h>
>>>    #include <linux/module.h>
>>>    #include <linux/platform_device.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/types.h>
>>>    #include <linux/dmi.h>
>>>    #include <linux/leds.h>
>>> +
>>> +#include <asm/byteorder.h>
>>> +
>>>    #include "alienware-wmi.h"
>>>    
>>>    MODULE_AUTHOR("Mario Limonciello <mario.limonciello@outlook.com>");
>>> @@ -150,21 +155,23 @@ u8 alienware_interface;
>>>    int alienware_wmi_command(struct wmi_device *wdev, u32 method_id,
>>>    			  void *in_args, size_t in_size, u32 *out_data)
>>>    {
>>> -	struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
>>> -	struct acpi_buffer in = {in_size, in_args};
>>> -	acpi_status ret;
>>> +	struct wmi_buffer out, in = {
>>> +		.data = in_args,
>>> +		.length = in_size,
>>> +	};
>>> +	int ret;
>>>    
>>> -	ret = wmidev_evaluate_method(wdev, 0, method_id, &in, out_data ? &out : NULL);
>>> -	if (ACPI_FAILURE(ret))
>>> -		return -EIO;
>>> -
>>> -	union acpi_object *obj __free(kfree) = out.pointer;
>>> +	if (out_data)
>>> +		ret = wmidev_invoke_method(wdev, 0, method_id, &in, &out,
>>> +					   sizeof(*out_data));
>>> +	else
>>> +		ret = wmidev_invoke_method(wdev, 0, method_id, &in, NULL, 0);
>>> +	if (ret)
>>> +		return ret;
>>>    
>>>    	if (out_data) {
>>> -		if (obj && obj->type == ACPI_TYPE_INTEGER)
>>> -			*out_data = (u32)obj->integer.value;
>>> -		else
>>> -			return -ENOMSG;
>>> +		__le32 *data __free(kfree) = out.data;
>>> +		*out_data = le32_to_cpu(*data);
>>>    	}
>> Hi,
>>
>> calling wmidev_invoke_method() with a NULL output buffer will likely lead to crashes. This happens
>> because wmidev_invoke_method() demands that a valid pointer to a output buffer is provided by the
>> caller. I suggest that you use wmidev_invoke_procedure() instead:
>>
>> 	__le32 *data __free(kfree) = NULL;
>>
>> 	if (!out_data)
>> 		return wmidev_invoke_procedure(wdev, 0, method_id, &in);
>>
>> 	ret = wmidev_invoke_method(wdev, 0, method_id, &in, &out, sizeof(*data));
>> 	if (ret < 0)
>> 		return ret;
>>
>> 	result = out.data
>> 	...
> Hi Armin,
>
> You're right, I thought the only difference between _procedure and
> _method was the size check.
>
> Also, Sashiko [1] reported that out.data might be ZERO_SIZE_PTR even if
> wmidev_invoke_method() succeeds. I thought it was a false positive but I
> looked further and it was actually a bug. I submitted a fix for this.

Thank you, i will take a look at it immediately.

Thanks,
Armin Wolf

>
> [1] https://sashiko.dev/#/patchset/20260428-aw-new-api-v4-1-d2c06241d7ad%40gmail.com
>