From 465dc9da8ff61a69e649ec2d402d8e06034f4585 Mon Sep 17 00:00:00 2001 From: Rong Zhang Date: Wed, 21 Jan 2026 02:20:02 +0800 Subject: [PATCH] platform/x86: lenovo-wmi-helpers: Convert returned buffer into u32 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Link: https://lore.kernel.org/r/f1787927-b655-4321-b9d9-bc12353c72db@gmx.de/ Signed-off-by: Rong Zhang Reviewed-by: Derek J. Clark Tested-by: Derek J. Clark Reviewed-by: Armin Wolf Link: https://patch.msgid.link/20260120182104.163424-2-i@rong.moe Reviewed-by: Ilpo Järvinen Signed-off-by: Ilpo Järvinen --- drivers/platform/x86/lenovo/wmi-helpers.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/platform/x86/lenovo/wmi-helpers.c b/drivers/platform/x86/lenovo/wmi-helpers.c index f6fef6296251e..7379defac5002 100644 --- a/drivers/platform/x86/lenovo/wmi-helpers.c +++ b/drivers/platform/x86/lenovo/wmi-helpers.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #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; -- 2.47.3