The recent changes to genpd makes a genpd OF provider that is powered-on at
initialization to stay powered-on, until the ->sync_state() callback is
invoked for it.

This may not happen at all, if we wait for a consumer device to be probed,
leading to wasting energy. There are ways to enforce the ->sync_state()
callback to be invoked, through sysfs or via the probe-defer-timeout, but
none of them in its current form are a good fit for rmobile-sysc PM
domains.

Let's therefore opt-out from this behaviour of genpd for now, by using the
GENPD_FLAG_NO_STAY_ON.

Link: https://lore.kernel.org/all/20250701114733.636510-1-ulf.hansson@linaro.org/
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Fixes: 0e789b491ba0 ("pmdomain: core: Leave powered-on genpds on until sync_state")
Fixes: 13a4b7fb6260 ("pmdomain: core: Leave powered-on genpds on until late_initcall_sync")
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/pmdomain/renesas/rmobile-sysc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pmdomain/renesas/rmobile-sysc.c b/drivers/pmdomain/renesas/rmobile-sysc.c
index 8eedc9a1d825..a6bf7295e909 100644
--- a/drivers/pmdomain/renesas/rmobile-sysc.c
+++ b/drivers/pmdomain/renesas/rmobile-sysc.c
@@ -100,7 +100,8 @@ static void rmobile_init_pm_domain(struct rmobile_pm_domain *rmobile_pd)
 	struct generic_pm_domain *genpd = &rmobile_pd->genpd;
 	struct dev_power_governor *gov = rmobile_pd->gov;
 
-	genpd->flags |= GENPD_FLAG_PM_CLK | GENPD_FLAG_ACTIVE_WAKEUP;
+	genpd->flags |= GENPD_FLAG_PM_CLK | GENPD_FLAG_ACTIVE_WAKEUP |
+		GENPD_FLAG_NO_STAY_ON;
 	genpd->attach_dev = cpg_mstp_attach_dev;
 	genpd->detach_dev = cpg_mstp_detach_dev;
 
-- 
2.43.0

On Tue, 9 Sept 2025 at 13:11, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> The recent changes to genpd makes a genpd OF provider that is powered-on at
> initialization to stay powered-on, until the ->sync_state() callback is
> invoked for it.
>
> This may not happen at all, if we wait for a consumer device to be probed,
> leading to wasting energy. There are ways to enforce the ->sync_state()
> callback to be invoked, through sysfs or via the probe-defer-timeout, but
> none of them in its current form are a good fit for rmobile-sysc PM
> domains.
>
> Let's therefore opt-out from this behaviour of genpd for now, by using the
> GENPD_FLAG_NO_STAY_ON.
>
> Link: https://lore.kernel.org/all/20250701114733.636510-1-ulf.hansson@linaro.org/
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Fixes: 0e789b491ba0 ("pmdomain: core: Leave powered-on genpds on until sync_state")
> Fixes: 13a4b7fb6260 ("pmdomain: core: Leave powered-on genpds on until late_initcall_sync")
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
On SH-Mobile AG5 (kzm9g) and R-Mobile A1 (armadillo).

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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