linux-kernel - Re: [PATCH] PM / Domains: Propagate start and restore errors during runtime resume

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Date:	Thu, 3 Mar 2016 21:32:06 +0100
From:	"Rafael J. Wysocki" <rafael@...nel.org>
To:	Kevin Hilman <khilman@...libre.com>
Cc:	Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Ulf Hansson <ulf.hansson@...aro.org>
Subject: Re: [PATCH] PM / Domains: Propagate start and restore errors during
 runtime resume

On Thu, Mar 3, 2016 at 9:24 PM, Kevin Hilman <khilman@...libre.com> wrote:
> Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com> writes:
>
>> During runtime resume the return values of the start and restore steps
>> are ignored. As a result drivers are not notified of runtime resume
>> failures and can't propagate them up. Fix it by returning an error if
>> either the start or restore step fails, and clean up properly in the
>> error path.
>>
>> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
>> ---
>>  drivers/base/power/domain.c | 20 ++++++++++++++++++--
>>  1 file changed, 18 insertions(+), 2 deletions(-)
>>
>> This fixes an issue I've noticed with my driver's .runtime_resume() handler
>> returning an error that was never propagated out of pm_runtime_get_sync().
>
> Acked-by: Kevin Hilman <khilman@...libre.com>
>
>> A second issue then appeared. The device .runtime_error field is set to the
>> error code returned by my .runtime_resume() handler, but it never reset. Any
>> subsequent try to resume the device fails with -EINVAL. I'm not sure what the
>> right way to solve that is, advices are welcome.
>
> Probably setting it (back) to zero after each successful runtime_suspend
> or runtime_resume is the right way.  Rafael?

That follows the assumption that runtime PM usually won't be reliable
after an error, so runtime_error has to be cleared explicitly via
pm_runtime_set_status().

Thanks,
Rafael