Re: [PATCH] pmdomain: core: switch to dynamic root device

[Geert Uytterhoeven]

On Tue, 9 Jun 2026 at 12:53, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> On Fri, 24 Apr 2026 at 12:41, Johan Hovold <johan@xxxxxxxxxx> wrote:
> > Driver core expects devices to be dynamically allocated and will, for
> > example, complain loudly if a device that lacks a release function is
> > ever freed.
> >
> > Use root_device_register() to allocate and register the root device
> > instead of open coding using a static device.
> >
> > Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
>
> Thanks for your patch, which is now commit a96e40f4afdcb52a
> ("pmdomain: core: switch to dynamic root device") in pmdomain/next.
> On e.g. R-Car H1, R-Car M2-W, and R-Car H3, this causes scary messages
> when systemd-journald.service is started:
>
>     synth uevent: /always-on: failed to send uevent
>     genpd_provider always-on: uevent: failed to send synthetic uevent: -22
>     synth uevent: /ca15-cpu0: failed to send uevent
>     genpd_provider ca15-cpu0: uevent: failed to send synthetic uevent: -22
>     [...]

I missed that there is another set on e.g. R-Car H1 for the clock domain:

    synth uevent: /clocks: failed to send uevent
    genpd_provider clocks: uevent: failed to send synthetic uevent: -22

>
> Reverting the commit fixes the issue.
>
> > --- a/drivers/pmdomain/core.c
> > +++ b/drivers/pmdomain/core.c
> > @@ -33,9 +33,7 @@ static const struct bus_type genpd_provider_bus_type = {
> >  };
> >
> >  /* The parent for genpd_provider devices. */
> > -static struct device genpd_provider_bus = {
> > -       .init_name = "genpd_provider",
> > -};
> > +static struct device *genpd_provider_bus;
> >
> >  #define GENPD_RETRY_MAX_MS     250             /* Approximate */
> >
> > @@ -2325,7 +2323,7 @@ static int genpd_alloc_data(struct generic_pm_domain *genpd)
> >         device_initialize(&genpd->dev);
> >         genpd->dev.release = genpd_provider_release;
> >         genpd->dev.bus = &genpd_provider_bus_type;
> > -       genpd->dev.parent = &genpd_provider_bus;
> > +       genpd->dev.parent = genpd_provider_bus;
> >
> >         if (!genpd_is_dev_name_fw(genpd)) {
> >                 dev_set_name(&genpd->dev, "%s", genpd->name);
> > @@ -3567,11 +3565,9 @@ static int __init genpd_bus_init(void)
> >  {
> >         int ret;
> >
> > -       ret = device_register(&genpd_provider_bus);
> > -       if (ret) {
> > -               put_device(&genpd_provider_bus);
> > -               return ret;
> > -       }
> > +       genpd_provider_bus = root_device_register("genpd_provider");
> > +       if (IS_ERR(genpd_provider_bus))
> > +               return PTR_ERR(genpd_provider_bus);
> >
> >         ret = bus_register(&genpd_provider_bus_type);
> >         if (ret)
> > @@ -3593,7 +3589,7 @@ static int __init genpd_bus_init(void)
> >  err_prov_bus:
> >         bus_unregister(&genpd_provider_bus_type);
> >  err_dev:
> > -       device_unregister(&genpd_provider_bus);
> > +       root_device_unregister(genpd_provider_bus);
> >         return ret;
> >  }
> >  core_initcall(genpd_bus_init);
>
> Apparently this is done too late for drivers/pmdomain/renesas/rcar-sysc.c,
> which registers PM domains from an early_initcall().  Doing all work in
> rcar-sysc.c from the postcore_initcall() is not an option, as the
> CPU power domains are needed for secondary CPU startup on R-Car H1.

Same story for cpg_mstp_add_clk_domain(), which is called from

    CLK_OF_DECLARE(r8a7778_cpg_clks, "renesas,r8a7778-cpg-clocks",
                   r8a7778_cpg_clocks_init);
    CLK_OF_DECLARE(r8a7779_cpg_clks, "renesas,r8a7779-cpg-clocks",
                   r8a7779_cpg_clocks_init);
    CLK_OF_DECLARE(rz_cpg_clks, "renesas,rz-cpg-clocks", rz_cpg_clocks_init);

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds