Re: [PATCH] pmdomain: core: Honour pd_ignore_unused in the sync_state power-off

[Geert Uytterhoeven]

Hi Joshua,

On Sat, 29 Aug 2026 at 21:51, Joshua Yeong
<joshua.yeong@xxxxxxxxxxxxxxxx> wrote:
> The pd_ignore_unused command line option is documented to "keep all
> power-domains already enabled by bootloader on, even if no driver has
> claimed them". On an OF platform it no longer does.
>
> Powering off unclaimed PM domains used to be the job of
> genpd_power_off_unused(), which bails out on the option.
> Commit 002ebddd695a ("pmdomain: core: Restore behaviour for disabling
> unused PM domains") stopped that late_initcall_sync from clearing
> stay_on, so it can no longer power off a PM domain that was found
> powered-on at initialization. The only remaining path that clears
> stay_on is ->sync_state(), and it never looked at the option, so an
> unclaimed PM domain that the bootloader left on is powered off there
> regardless.
>
> Honour the option in the sync_state paths, for the PM domains that have
> no consumer attached. Those are the ones the option describes, and once
> genpd_power_off_unused() has bailed out they have no other power-off
> trigger, so they stay on as documented.
>
> The stay_on constraint is dropped either way, leaving the lifetime of
> the constraint unchanged. The PM domains that do have a consumer
> attached therefore stay under the control of runtime PM, which the
> option has never covered, and a PM domain that gains a consumer after
> ->sync_state() is not left pinned.
>
> Fixes: 0e789b491ba0 ("pmdomain: core: Leave powered-on genpds on until sync_state")
> Signed-off-by: Joshua Yeong <joshua.yeong@xxxxxxxxxxxxxxxx>

Thanks for your patch!

I did something similar in "[PATCH/RFC] pmdomain: core: Support
pd_ignore_unused with sync_state"[1], and Ulf responded[2]:

   "Right, I think it's time to consider removing it, unless people still
    find it useful ofcourse."

[1] https://lore.kernel.org/1cfa86b72b2a5aa2ade92f247dd318c9cb6ef2a1.1771267504.git.geert+renesas@xxxxxxxxx
[2] https://lore.kernel.org/CAPDyKFq2it5TAEBBKBh+q+UiRsGYaORar0Q_42LCuxyKRLYj0A@xxxxxxxxxxxxxx

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