Re: [PATCH v4 6/6] PM / Domains: Stop deferring probe at the end of initcall

[Ulf Hansson]

On 9 July 2018 at 17:41, Rob Herring <robh@xxxxxxxxxx> wrote:
> All PM domain drivers must be built-in (at least those using DT), so
> there is no point deferring probe after initcalls are done. Continuing
> to defer probe may prevent booting successfully even if managing PM
> domains is not required. This can happen if the user failed to enable
> the driver or if power-domains are added to a platform's DT, but there
> is not yet a driver (e.g. a new DTB with an old kernel).
>
> Call the driver core function driver_deferred_probe_check_init_done()
> instead of just returning -EPROBE_DEFER to stop deferring probe when
> initcalls are done.
>
> Acked-by: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
> Cc: Kevin Hilman <khilman@xxxxxxxxxx>
> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Cc: Pavel Machek <pavel@xxxxxx>
> Cc: Len Brown <len.brown@xxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: linux-pm@xxxxxxxxxxxxxxx
> Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
> ---
> v4:
>  - Add Rafael's ack
>
> v3:
>   - Update to new function name
>
>  drivers/base/power/domain.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 4925af5c4cf0..8c12213875c6 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -2253,7 +2253,7 @@ static int __genpd_dev_pm_attach(struct device *dev, struct device_node *np,
>                 mutex_unlock(&gpd_list_lock);
>                 dev_dbg(dev, "%s() failed to find PM domain: %ld\n",
>                         __func__, PTR_ERR(pd));
> -               return -EPROBE_DEFER;
> +               return driver_deferred_probe_check_state(dev);
>         }

This isn't the only error path where -EPROBE_DEFER may be returned
during attach in genpd.

Have a look at the callers of __genpd_dev_pm_attach() and also have a
second look inside __genpd_dev_pm_attach() itself. And in Rafael's
tree.

>
>         dev_dbg(dev, "adding to PM domain %s\n", pd->name);
> --
> 2.17.1

Besides the above, I am fine with the approach as such.

Kind regards
Uffe