On 2/8/24 10:22 AM, Armin Wolf wrote: > Am 08.02.24 um 03:41 schrieb Kuppuswamy Sathyanarayanan: > >> On 2/7/24 12:20 PM, Armin Wolf wrote: >>> The ACPI-WMI specification declares that a WMxx control method takes >>> 3 arguments: instance, method id and argument buffer. This is also >>> the case even when the underlying WMI method does not have any >>> input arguments. >> It would be better if you include specification version and section >> title for reference. > > The ACPI-WMI specification is not part of the ACPI specification. It > consists of a single whitepaper published by Microsoft: > > https://github.com/microsoft/Windows-driver-samples/blob/main/wmi/wmiacpi/wmi-acpi.htm > > The section describing the ACPI control methods is called > "ACPI Control Method Naming Conventions and Functionality for Windows 2000 Instrumentation". > > I do not thing that mentioning this in the commit message would be of any use. I think it is better to include this detail. But, since it is not a standard specification, I will let maintainer make this call. > >>> So if a WMI driver evaluates a WMI method without passing an input >>> buffer, ACPICA will log a warning complaining that the third argument >>> is missing. >> I assume it is a compile warning. Can you copy the warning message? > > Its not a compiler warning. > > The ACPI control method is being evaluated at runtime, so the warning message > will also be generated at runtime (when interpreting the AML bytecode). > Got it. > Thanks, > Armin Wolf > >>> Prevent this by checking that a input buffer was passed, and return >>> an error if this was not the case. >>> >>> Tested on a Asus PRIME B650-Plus. >>> >>> Signed-off-by: Armin Wolf <W_Armin@xxxxxx> >>> --- >> >> With above fixed, >> >> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> >> >>> drivers/platform/x86/wmi.c | 21 ++++++++++----------- >>> 1 file changed, 10 insertions(+), 11 deletions(-) >>> >>> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c >>> index 63906fdd0abf..f9e23d491dd9 100644 >>> --- a/drivers/platform/x86/wmi.c >>> +++ b/drivers/platform/x86/wmi.c >>> @@ -296,7 +296,7 @@ EXPORT_SYMBOL_GPL(wmidev_instance_count); >>> * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba >>> * @instance: Instance index >>> * @method_id: Method ID to call >>> - * @in: Buffer containing input for the method call >>> + * @in: Mandatory buffer containing input for the method call >>> * @out: Empty buffer to return the method results >>> * >>> * Call an ACPI-WMI method, the caller must free @out. >>> @@ -326,7 +326,7 @@ EXPORT_SYMBOL_GPL(wmi_evaluate_method); >>> * @wdev: A wmi bus device from a driver >>> * @instance: Instance index >>> * @method_id: Method ID to call >>> - * @in: Buffer containing input for the method call >>> + * @in: Mandatory buffer containing input for the method call >>> * @out: Empty buffer to return the method results >>> * >>> * Call an ACPI-WMI method, the caller must free @out. >>> @@ -347,26 +347,25 @@ acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 met >>> block = &wblock->gblock; >>> handle = wblock->acpi_device->handle; >>> >>> + if (!in) >>> + return AE_BAD_DATA; >>> + >>> if (!(block->flags & ACPI_WMI_METHOD)) >>> return AE_BAD_DATA; >>> >>> if (block->instance_count <= instance) >>> return AE_BAD_PARAMETER; >>> >>> - input.count = 2; >>> + input.count = 3; >>> input.pointer = params; >>> + >>> params[0].type = ACPI_TYPE_INTEGER; >>> params[0].integer.value = instance; >>> params[1].type = ACPI_TYPE_INTEGER; >>> params[1].integer.value = method_id; >>> - >>> - if (in) { >>> - input.count = 3; >>> - >>> - params[2].type = get_param_acpi_type(wblock); >>> - params[2].buffer.length = in->length; >>> - params[2].buffer.pointer = in->pointer; >>> - } >>> + params[2].type = get_param_acpi_type(wblock); >>> + params[2].buffer.length = in->length; >>> + params[2].buffer.pointer = in->pointer; >>> >>> get_acpi_method_name(wblock, 'M', method); >>> >>> -- >>> 2.39.2 >>> >>> > -- Sathyanarayanan Kuppuswamy Linux Kernel Developer
