Re: [PATCH rtw-next] wifi: rtw89: acpi: check for _DSM function support before evaluating it

[Rosen Penev]

On Sun, Nov 1, 2026 at 7:28 PM Ping-Ke Shih <pkshih@xxxxxxxxxxx> wrote:
>
> Rosen Penev <rosenp@xxxxxxxxx> wrote:
> > When the WiFi device has no ACPI companion, or the firmware does not
> > implement a given rtw89 _DSM function, rtw89_acpi_evaluate_dsm() calls
> > acpi_evaluate_dsm() anyway. ACPI core then warns on every probe:
> >
> >   ACPI: \: failed to evaluate _DSM e8c3a8d2-694b-004f-82bd-fe8607803aa7 rev:0 func:10 (0x1001)
> >   ACPI: \: failed to evaluate _DSM e8c3a8d2-694b-004f-82bd-fe8607803aa7 rev:0 func:6 (0x1001)
> >
> > Here the handle is NULL, and acpi_evaluate_object() returns
> > AE_BAD_PARAMETER. All callers already treat failure as "no policy
> > provided by the platform", so this is only noise.
> >
> > Use acpi_check_dsm() first. It returns false for a NULL handle and for
> > functions that are not advertised, so absent functions fail quietly at
> > debug level, as rtw89_acpi_evaluate_method() already does.
>
> The acpi_check_dsm() is to evaluate func 0 before actually accessing func.
> I'm not sure if all platforms will implement func 0. Do you know that?
yes this was only a partial fix. Will rework.
>
> >
> > Seen on an RTL8852BE in a desktop PCIe slot.
> >
> > Fixes: e897b0bef38a ("wifi: rtw89: introduce realtek ACPI DSM method")
>
> Does it need a Fixes? As I see, this is not a bug.
WIll drop.
>
> > Signed-off-by: Rosen Penev <rosenp@xxxxxxxxx>
>
>