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From:   Chris Chiu <chiu@endlessm.com>
To:     dvhart@infradead.org, andy@infradead.org, hdegoede@redhat.com,
        gregkh@linuxfoundation.org, gayatri.kammela@intel.com,
        mika.westerberg@linux.intel.com
Cc:     platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux@endlessm.com, Chris Chiu <chiu@endlessm.com>
Subject: [PATCH] platform/x86: asus_wmi: Reserve more space for struct bias_args
Date:   Fri, 22 May 2020 15:44:24 +0800
Message-Id: <20200522074424.54264-1-chiu@endlessm.com>
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Sender: linux-kernel-owner@vger.kernel.org
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On the ASUS laptop UX325JA/UX425JA, most of the media keys are not
working due to the ASUS WMI driver fails to be loaded. The ACPI error
as follows leads to the failure of asus_wmi_evaluate_method.
  ACPI BIOS Error (bug): AE_AML_BUFFER_LIMIT, Field [IIA3] at bit offset/length 96/32 exceeds size of target Buffer (96 bits) (20200326/dsopcode-203)
  No Local Variables are initialized for Method [WMNB]
  ACPI Error: Aborting method \_SB.ATKD.WMNB due to previous error (AE_AML_BUFFER_LIMIT) (20200326/psparse-531)

The DSDT for the WMNB part shows that 5 DWORD required for local
variables and the 3rd variable IIA3 hit the buffer limit.

Method (WMNB, 3, Serialized)
{ ..
    CreateDWordField (Arg2, Zero, IIA0)
    CreateDWordField (Arg2, 0x04, IIA1)
    CreateDWordField (Arg2, 0x08, IIA2)
    CreateDWordField (Arg2, 0x0C, IIA3)
    CreateDWordField (Arg2, 0x10, IIA4)
    Local0 = (Arg1 & 0xFFFFFFFF)
    If ((Local0 == 0x54494E49))
  ..
}

The limitation is determined by the input acpi_buffer size passed
to the wmi_evaluate_method. Since the struct bios_args is the data
structure used as input buffer by default for all ASUS WMI calls,
the size needs to be expanded to fix the problem.

Signed-off-by: Chris Chiu <chiu@endlessm.com>
---
 drivers/platform/x86/asus-wmi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index bb7c529d7d16..cd212ee210e2 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -116,6 +116,8 @@ struct bios_args {
 	u32 arg0;
 	u32 arg1;
 	u32 arg2; /* At least TUF Gaming series uses 3 dword input buffer. */
+	u32 arg4;
+	u32 arg5;
 } __packed;
 
 /*
-- 
2.25.2