Re: [PATCH v3 0/4] ACPI: scan: Adjust power management initialization and PCI devices handling

[Rafael J. Wysocki (Intel)]

On Fri, Sep 4, 2026 at 11:41 AM Peixin Xie
<peixin.xie@xxxxxxxxxxxxxxxxxx> wrote:
>
> Hi Rafael,
>
> On Thu, 03 Sep 2026 18:57:09 +0200, Rafael J. Wysocki wrote:
> > Hi All,
> >
> > This is an update of
> >
> > https://lore.kernel.org/linux-acpi/5144065.31r3eYUQgx@rafael.j.wysocki/
> >
> > that adds 1 patch, 3 two patches, and addresses review comments in patch [2/4].
> >
> > The new patch drops in v3 is a cleanup relocating the acpi_bus_init_power()
> > declaration to an internal header file in the core ACPI support code (patch
> > [3/4]).
> >
> > One of the patches dropped from the v2 has been folded into patch [2/4]
> > and the other two have become cleanups on top of this series that can be
> > done later.
> >
> > Overall, the series aims at addressing a few issues present in the core ACPI
> > device enumeration code, mostly related to the acpi_bus_attach() function.
> >
> > The first one is that, on some systems, ACPI power management is initialized
> > twice for devices that have missing dependencies to start with.  An attempt
> > to address this issue had been made during the 7.3 merge window, but it had
> > to be reverted [1].  The approach used here is roughly the same as in the
> > reverted commit, but it takes PCI devices (which are a special case) into
> > account.
> >
> > In addition to the above, ACPI power management may be initialized prematurely
> > for device objects whose parents are not ready for enumeration.
> >
> > The other issues are that flags are unnecessarily cleared by acpi_bus_attach()
> > for devices with missing dependencies and PCI devices are handled by
> > acpi_bus_attach() like any other devices which is a mistake.
> >
> > Please see the changelogs of individual patches for details.
> >
> > Thanks!
> >
> >
> > Link: https://lore.kernel.org/linux-acpi/20260820-acpi-power-resource-ref-fix-v2-1-29818173ea13@xxxxxxxxxxxxxxxxxx/ [1]
>
> I tested the complete v3 series on the SpacemiT K3 RISC-V Pico-ITX platform
> where the original duplicate ACPI PowerResource reference issue was
> observed.
>
> The power resource left on by firmware is now turned off as unused after
> the namespace scan. After the device dependency is satisfied, the power
> resource is turned on once for the device and is turned off normally
> during runtime suspend. Runtime resume also works correctly.
>
> Tested-by: Peixin Xie <peixin.xie@xxxxxxxxxxxxxxxxxx>

Thank you!