[PATCH 1/9] i2c: designware: Fix system suspend

[Rafael J. Wysocki]

On Wednesday, June 28, 2017 04:01:39 PM Ulf Hansson wrote:
> On 27 June 2017 at 09:55, Jarkko Nikula <jarkko.nikula at linux.intel.com> wrote:
> > On 06/22/2017 02:16 PM, Jarkko Nikula wrote:
> >>
> >> On 06/22/2017 01:49 PM, Mika Westerberg wrote:
> >>>
> >>> On Thu, Jun 22, 2017 at 01:31:51AM +0200, Rafael J. Wysocki wrote:
> >>>>
> >>>> On Wed, Jun 21, 2017 at 9:21 PM, Ulf Hansson <ulf.hansson at linaro.org>
> >>>> wrote:
> >>>
> >>> Thanks Ulf for taking care of this!
> >>>
> >> Indeed!
> >>
> >>> I tested this series on Dell XPS 9350 which has touch panel connected to
> >>> I2C and suspend/resume still works fine and I can see the controller
> >>> going to D3 when the touch panel is idle.
> >>>
> >>> I can perform more comprehensive testing next week.
> >>>
> >> Unfortunately I'm seeing interrupt storm during suspend/resume on
> >> platform using PM domain from drivers/acpi/acpi_lpss.c straight after
> >> this patch. Maybe some timing related as I see it only if I have debug
> >> messages on (i2c_designware_core.dyndbg=+p). But it occurs only after
> >> this patch.
> >>
> > Sorry the noise, this was bogus. That platform is doing this interrupt storm
> > randomly and it occurs also without the patch.
> 
> 
> Okay, then it seems like we should go with $subject patch, although
> allow me to update the changelog and post a new version.

But as I said, it would be better to do the pm_runtime_resume() in ->resume
(unless that breaks something), for two reasons.

The first reason is that ->complete is synchronous and ->resume can be done
in parallel with other devices which potentially saves time.  The second reason
is that it wouldn't interfere with direct_complete on systems where that
actually works.

Thanks,
Rafael