[alsa-devel] [PATCH v9 2/3] x86: add support for Huawei WMI hotkeys.

[ayman.bagabas at gmail.com]

On Fri, 2018-12-07 at 00:52 -0500, ayman.bagabas at gmail.com wrote:
On Mon, 2018-12-03 at 21:17 +0200, Andy Shevchenko wrote:
> On Mon, Dec 3, 2018 at 9:04 PM Takashi Iwai <tiwai at suse.de> wrote:
> > On Mon, 03 Dec 2018 19:53:39 +0100,
> > Ayman Bagabas wrote:
> > > +     if (code == 0x80) {
> > > +             acpi_status status;
> > > +             acpi_handle handle;
> > > +             unsigned long long result;
> > > +             union acpi_object args[1];
> > > +             struct acpi_object_list arg_list = {
> > > +                     .pointer = args,
> > > +                     .count = ARRAY_SIZE(args),
> > > +             };
> > > +
> > > +             args[0].type = ACPI_TYPE_INTEGER;
> > > +             args[0].integer.value = 0;
> > > +
> > > +             status = acpi_get_handle(NULL, "\\WMI0", &handle);
> > > +             if (ACPI_FAILURE(status)) {
> > > +                     dev_err(&wdev->dev, "Unable to get ACPI
> > > handle\n");
> > > +                     return;
> > > +             }
> > > +
> > > +             status = acpi_evaluate_integer(NULL, "WQ00",
> > > &arg_list, &result);
> > 
> > I guess you need to pass handle here?  In the earlier version, you
> > passed \\WMI0.WQ00, so it worked with NULL handle.  But now it's no
> > longer so...
> 
> I think in this case we don't need to have a separate call to get
> handle and try to get integer directly. In either we will have an
> error case if method  / namespace / etc is not found.
> 
> 

I was digging further into the DSDT table of the laptop that has WQ00
method and it turned out that this method is a ACPI_WMI_EXPENSIVE. It
has its own GUID of "39142400-C6A3-40fa-BADB-8A2652834100". I believe
wmi_query_block, which is deprecated BTW, can be used to access this
method instead of acpi_evaluate. However, I don't have a machine to
test it on. Any ideas?