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platform/x86: lenovo-wmi-helpers: Convert returned buffer into u32

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The Windows WMI-ACPI driver converts all ACPI objects into a common
buffer format, so returning a buffer with four bytes will look like an
integer for WMI consumers under Windows.

Therefore, some devices may simply implement the corresponding ACPI
methods to always return a buffer. While lwmi_dev_evaluate_int() expects
an integer (u32), convert returned >=4B buffer into u32 to support these
devices.

Suggested-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/f1787927-b655-4321-b9d9-bc12353c72db@gmx.de/
Signed-off-by: Rong Zhang <i@rong.moe>
Reviewed-by: Derek J. Clark <derekjohn.clark@gmail.com>
Tested-by: Derek J. Clark <derekjohn.clark@gmail.com>
Reviewed-by: Armin Wolf <W_Armin@gmx.de>
Link: https://patch.msgid.link/20260120182104.163424-2-i@rong.moe
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
This commit is contained in:
Rong Zhang
2026-01-21 02:20:02 +08:00
committed by Ilpo Järvinen
parent 2177a02246
commit 465dc9da8f
1 changed files with 18 additions and 3 deletions
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21
drivers/platform/x86/lenovo/wmi-helpers.c
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@@ -21,6 +21,7 @@
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/unaligned.h>
#include <linux/wmi.h>
#include "wmi-helpers.h"
@@ -59,10 +60,24 @@ int lwmi_dev_evaluate_int(struct wmi_device *wdev, u8 instance, u32 method_id,
if (!ret_obj)
return -ENODATA;
if (ret_obj->type != ACPI_TYPE_INTEGER)
return -ENXIO;
switch (ret_obj->type) {
/*
* The ACPI method may simply return a buffer when a u32
* is expected. This is valid on Windows as its WMI-ACPI
* driver converts everything to a common buffer.
*/
case ACPI_TYPE_BUFFER:
if (ret_obj->buffer.length < sizeof(u32))
return -ENXIO;
*retval = (u32)ret_obj->integer.value;
*retval = get_unaligned_le32(ret_obj->buffer.pointer);
return 0;
case ACPI_TYPE_INTEGER:
*retval = (u32)ret_obj->integer.value;
return 0;
default:
return -ENXIO;
}
}
return 0;