Re: [PATCH v3 21/24] pmdomain: core: Leave powered-on genpds on until late_initcall_sync

[Jon Hunter]

On 15/07/2025 12:34, Ulf Hansson wrote:

...

> > > Have you found any resolution for this? I have also noticed a boot
> > > regression on one of our Tegra210 boards and bisect is pointing to this
> > > commit. I don't see any particular crash, but a hang on boot.
> >
> > Thanks for reporting!
> >
> > For Exynos we opt-out from the behaviour by enforcing a sync_state of
> > all PM domains upfront [1], which means before any devices get
> > attached.
> >
> > Even if that defeats the purpose of the $subject series, this was one
> > way forward that solved the problem. When the boot-ordering problem
> > (that's how I understood the issue) for Exynos gets resolved, we
> > should be able to drop the hack, at least that's the idea.
> >
> > > If there is any debug we can enable to see which pmdomain is the problem
> > > let me know.
> >
> > There aren't many debug prints in genpd that I think makes much sense
> > to enable, but you can always give it a try. Since you are hanging,
> > obviously you can't look at the genpd debugfs data...
> >
> > Note that, the interesting PM domains are those that are powered-on
> > when calling pm_genpd_init(). As a start, I would add some debug
> > prints in () to see which PM domains that are relevant to track.
>
> /s/()/tegra_powergate_add()


I have been able to track this down to a problem in the Tegra PMC driver 
where we are registering the power-domains and I have sent a fix [0]. 
Looks like we have been getting lucky up until now.

Cheers!
Jon

[0] 
https://lore.kernel.org/linux-tegra/20250731121832.213671-1-jonathanh@xxxxxxxxxx/T/#u

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