Re: [PATCH] PM / Domains: defer dev_pm_domain_set() until genpd->attach_dev succeeds if present

From: Kevin Hilman
Date: Tue Jul 11 2017 - 14:53:17 EST

"Rafael J. Wysocki" <rafael@xxxxxxxxxx> writes:

> On Thu, Jun 29, 2017 at 8:00 PM, Sudeep Holla <sudeep.holla@xxxxxxx> wrote:
>> If the genpd->attach_dev or genpd->power_on fails, genpd_dev_pm_attach
>> may return -EPROBE_DEFER initially. However genpd_alloc_dev_data sets
>> the PM domain for the device unconditionally.
>> When subsequent attempts are made to call genpd_dev_pm_attach, it may
>> return -EEXISTS checking dev->pm_domain without re-attempting to call
>> attach_dev or power_on.
>> platform_drv_probe then attempts to call drv->probe as the return value
>> -EEXIST != -EPROBE_DEFER, which may end up in a situation where the
>> device is accessed without it's power domain switched on.
>> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
>> Cc: Kevin Hilman <khilman@xxxxxxxxxx>
>> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
>> Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> Ulf, this looks like a genuine fix to me, any comments?

This looks like the right fix to me.

Acked-by: Kevin Hilman <khilman@xxxxxxxxxxxx>