[PATCH 03/11] platform/x86: asus-wmi: Increase input buffer size of WMI methods

[Yurii Pavlovskyi <yurii.pavlovskyi@gmail.com>]

The asus-nb-wmi driver is matched by WMI alias but fails to load on TUF
Gaming series laptops producing multiple ACPI errors in kernel log. Patch
was tested on TUF Gaming FX505GM and older K54C model.

The input buffer for WMI method invocation size is 2 dwords, whereas
3 are expected by this model.

FX505GM:
..
Method (WMNB, 3, Serialized)
{
    P8XH (Zero, 0x11)
    CreateDWordField (Arg2, Zero, IIA0)
    CreateDWordField (Arg2, 0x04, IIA1)
    CreateDWordField (Arg2, 0x08, IIA2)
    Local0 = (Arg1 & 0xFFFFFFFF)
    ...

Compare with older K54C:
...
Method (WMNB, 3, NotSerialized)
{
    CreateDWordField (Arg2, 0x00, IIA0)
    CreateDWordField (Arg2, 0x04, IIA1)
    Local0 = (Arg1 & 0xFFFFFFFF)
    ...

Increase buffer size to 3 dwords. No negative consequences of this change
are expected, as input buffer size is not verified. The original function
is replaced by a wrapper for a new method passing value 0 for the last
parameter. The new function will be used to control RGB keyboard
backlight.

Signed-off-by: Yurii Pavlovskyi <yurii.pavlovskyi@gmail.com>
---
One of current kernel errors:
ACPI BIOS Error (bug): AE_AML_BUFFER_LIMIT, Field [IIA2] at bit offset/
	length 64/32 exceeds size of target Buffer (64 bits)
	(20190215/dsopcode-203)
[ 4528.573948] No Local Variables are initialized for Method [WMNB]
[ 4528.573949] Initialized Arguments for Method [WMNB]:  (3 arguments
	defined for method invocation)
[ 4528.573950]   Arg0:   00000000bd1bea5a <Obj>
	Integer 0000000000000000
[ 4528.573952]   Arg1:   00000000d414dc53 <Obj>
	Integer 000000004E464741
[ 4528.573954]   Arg2:   00000000fcefea4b <Obj>
	Buffer(8) F0 95 08 00 00 00 00 00
[ 4528.573959] ACPI Error: Aborting method \_SB.ATKD.WMNB due to previous
	error (AE_AML_BUFFER_LIMIT) (20190215/psparse-531)
[ 4528.686425] asus-nb-wmi: probe of asus-nb-wmi failed with error -5
---
 drivers/platform/x86/asus-wmi.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 0fbb947b07c4..cfccfc0b8c2f 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -95,6 +95,7 @@ static bool ashs_present(void)
 struct bios_args {
 	u32 arg0;
 	u32 arg1;
+	u32 arg2; /* At least TUF Gaming series uses 3 dword input buffer. */
 } __packed;
 
 /*
@@ -220,11 +221,13 @@ static void asus_wmi_input_exit(struct asus_wmi *asus)
 	asus->inputdev = NULL;
 }
 
-int asus_wmi_evaluate_method(u32 method_id, u32 arg0, u32 arg1, u32 *retval)
+static int asus_wmi_evaluate_method_3dw(u32 method_id, u32 arg0, u32 arg1,
+		u32 arg2, u32 *retval)
 {
 	struct bios_args args = {
 		.arg0 = arg0,
 		.arg1 = arg1,
+		.arg2 = arg2
 	};
 	struct acpi_buffer input = { (acpi_size) sizeof(args), &args };
 	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
@@ -256,6 +259,11 @@ int asus_wmi_evaluate_method(u32 method_id, u32 arg0, u32 arg1, u32 *retval)
 
 	return 0;
 }
+
+int asus_wmi_evaluate_method(u32 method_id, u32 arg0, u32 arg1, u32 *retval)
+{
+	return asus_wmi_evaluate_method_3dw(method_id, arg0, arg1, 0, retval);
+}
 EXPORT_SYMBOL_GPL(asus_wmi_evaluate_method);
 
 static int asus_wmi_evaluate_method_agfn(const struct acpi_buffer args)
-- 
2.17.1