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

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Date:   Wed, 21 Jun 2017 21:52:12 +0000
From:   <Mario.Limonciello@...l.com>
To:     <pali.rohar@...il.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

> -----Original Message-----
> From: Pali Rohár [mailto:pali.rohar@...il.com]
> Sent: Saturday, June 17, 2017 11:35 AM
> To: Limonciello, Mario <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?
> 

Instance count is 1.

Thanks,