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

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Date:	Thu, 3 Mar 2016 21:34:04 +0100
From:	"Rafael J. Wysocki" <rafael@...nel.org>
To:	"Rafael J. Wysocki" <rafael@...nel.org>
Cc:	Kevin Hilman <khilman@...libre.com>,
	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 9:32 PM, Rafael J. Wysocki <rafael@...nel.org> wrote:
> 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().

Sorry, that won't work.

Anyway, the idea is that the error has to be cleared manually after a failure.