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

From: Mario.Limonciello
Date: Thu Jun 15 2017 - 11:16:42 EST


> -----Original Message-----
> From: Pali RohÃr [mailto:pali.rohar@xxxxxxxxx]
> Sent: Thursday, June 15, 2017 8:59 AM
> To: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>; Darren Hart
> <dvhart@xxxxxxxxxxxxx>
> Cc: Andy Shevchenko <andy@xxxxxxxxxxxxx>; Andy Lutomirski <luto@xxxxxxxxxx>;
> platform-driver-x86@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> 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.

> On Wednesday 14 June 2017 17:46:54 Pali RohÃr wrote:
> > Function wmi_evaluate_method:
> ...
> > alienware-wmi.c:
> > instance=1 /* no comment why, guid=A70591CE-A997-11DA-B012-
> B622A1EF5492 */
> > instance=1 /* no comment why, guid=A80593CE-A997-11DA-B012-
> B622A1EF5492 */
> > instance=1 /* no comment why, guid=A70591CE-A997-11DA-B012-
> B622A1EF5492 */
> ...
> > dell-wmi-led.c:
> > instance=1 /* no comment why, guid=F6E4FE6E-909D-47cb-8BAB-
> C9F6F2F8D396 */
>
> --
> Pali RohÃr
> pali.rohar@xxxxxxxxx