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

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Date:	Thu, 03 Mar 2016 22:40:57 +0200
From:	Laurent Pinchart <laurent.pinchart@...asonboard.com>
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

Hi Rafael,

On Thursday 03 March 2016 21:34:04 Rafael J. Wysocki wrote:
> 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.

Thanks for the advice, I'll try doing so in my driver.

-- 
Regards,

Laurent Pinchart