Re: [PATCH v2 2/8] cpuidle: psci: Transition to the faux device interface

[Jon Hunter]

On 01/05/2025 17:07, Sudeep Holla wrote:

...

> > I have noticed the following error messages on some of our Tegra devices ...
> >
> >   ERR KERN faux psci-cpuidle: probe did not succeed, tearing down the device
> >   ERR KERN CPUidle PSCI: Failed to create psci-cpuidle device
> >
> > I had a quick look at this and this occurs because of the following code in
> > the probe cpuidle-psci driver ...
> >
> >          /*
> >           * If no DT idle states are detected (ret == 0) let the driver
> >           * initialization fail accordingly since there is no reason to
> >           * initialize the idle driver if only wfi is supported, the
> >           * default archictectural back-end already executes wfi
> >           * on idle entry.
> >           */
> >          ret = dt_init_idle_driver(drv, psci_idle_state_match, 1);
> >          if (ret <= 0)
> >                  return ret ? : -ENODEV;
> >
> >
> > So although it could be argued that the error message is valid, I am not
> > sure if there is anything that mandates that we need to have the idle-states
> > present.
> >
> > We are always checking for new kernel errors and so if something new occurs,
> > I am trying to figure out what is the correct way to fix. For this case I am
> > not sure what is best.
>
> This is another case where probe was failing before too just that faux
> device probe throws the error. I will take a look and see what can be done.
> But yes, we shouldn't throw error if no idle-states are present in the DT.


Yes exactly this was already failing. Thanks for taking a look!

Cheers
Jon

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nvpublic