Re: [PATCH v2] PM / Domains: defer dev_pm_domain_set() until genpd->attach_dev succeeds if present

[Sudeep Holla <sudeep.holla@arm.com>]

On 17/07/17 08:01, Ulf Hansson wrote:
> On 14 July 2017 at 12:51, Sudeep Holla <sudeep.holla@arm.com> 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.
>>
>> Fixes: f104e1e5ef57 ("PM / Domains: Re-order initialization of generic_pm_domain_data")
>> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
>> Cc: Kevin Hilman <khilman@kernel.org>
>> Cc: Ulf Hansson <ulf.hansson@linaro.org>
>> Cc: <stable@vger.kernel.org> # v4.0+
>> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> 
> Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
> 
>> ---
>>  drivers/base/power/domain.c | 8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> Hi,
>>
>> I have added Cc/Fixes tags based on the original commit that caused the issue.
>> I need to workout a patch that can cleanly apply before commit 989561de9b51
>> ("PM / Domains: add setter for dev.pm_domain"), i.e. for v4.0.x to v4.4.x
>> This patch should apply from v4.5.x onwards.
> 
> Thanks for checking this.
> 
> Perhaps we should change the stable tag to # v4.5+ instead then?
> Otherwise the stable people will just report problems when trying to
> apply it.
> 

Yes, I know. I thought then I can work out the solution for whatever
version they need. Instead of trying to post patch for all versions from
v4.0 to v4.4
If that's not acceptable, then yes it should be #4.5+
Rafael, can you just update that if required ?

I am fine to work a patch for v4.[0-4].x when requested.

-- 
Regards,
Sudeep