linux-kernel - Re: [PATCH] RFC: platform/x86: wmi: Fix check for method instance number

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Date:   Sat, 17 Jun 2017 18:34:36 +0200
From:   Pali Rohár <pali.rohar@...il.com>
To:     Mario.Limonciello@...l.com
Cc:     dvhart@...radead.org, andy@...radead.org, luto@...nel.org,
        platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] RFC: platform/x86: wmi: Fix check for method instance number

On Friday 16 June 2017 18:33:54 Mario.Limonciello@...l.com wrote:
> > -----Original Message-----
> > From: Limonciello, Mario
> > Sent: Thursday, June 15, 2017 10:16 AM
> > To: 'Pali Rohár' <pali.rohar@...il.com>; Darren Hart
> > <dvhart@...radead.org> Cc: Andy Shevchenko <andy@...radead.org>;
> > Andy Lutomirski <luto@...nel.org>;
> > platform-driver-x86@...r.kernel.org; linux-kernel@...r.kernel.org
> > Subject: RE: [PATCH] RFC: platform/x86: wmi: Fix check for method
> > instance number
> > 
> > > -----Original Message-----
> > > From: Pali Rohár [mailto:pali.rohar@...il.com]
> > > Sent: Thursday, June 15, 2017 8:59 AM
> > > To: Limonciello, Mario <Mario_Limonciello@...l.com>; Darren Hart
> > > <dvhart@...radead.org>
> > > Cc: Andy Shevchenko <andy@...radead.org>; Andy Lutomirski
> > 
> > <luto@...nel.org>;
> > 
> > > platform-driver-x86@...r.kernel.org; linux-kernel@...r.kernel.org
> > > Subject: Re: [PATCH] RFC: platform/x86: wmi: Fix check for method
> > > instance number
> > > 
> > > Mario, are you able to check if instance number passed to
> > > wmi_evaluate_method in following dell WMI drivers is correct and
> > > should be really 1?
> > > 
> > > I suspect that it should be zero, as instance number is indexed
> > > from zero.
> > > 
> > > There is no comment in those dell WMI drivers why it is 1, nor
> > > what 1 means.
> > > 
> > > Ideally it needs to be checked in ACPI byte code, MOF file and
> > > WDG dump.
> > 
> > I think you're likely correct.  I don't have a box that supports
> > alienware-wmi or dell-wmi-led.c handy at the current moment to
> > confirm this hypothesis though. I'll confirm this later.
> > 
> > I didn't realize it was zero indexed when I wrote alienware-wmi,
> > and I'm guessing the author of dell-wmi-led didn't either.
> > 
> > The reason it's probably working is the ACPI byte code isn't
> > actually checking the instance since most times _WDG will only
> > call out one instance.
> 
> I confirmed you're correct.  Switching instance over to 0 works
> properly on an ASM200 (supported by alienware-wmi).

Can you check what is the value in the instance_count in _WDG?

-- 
Pali Rohár
pali.rohar@...il.com

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