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

Armin Wolf
2026-04-28T19:27:08Z

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
>