Re: [PATCH] hid: intel_ish-hid: ipc: register more pm callbacks to support hibernation

From: Srinivas Pandruvada
Date: Tue Jun 12 2018 - 11:30:37 EST

On Tue, 2018-06-12 at 16:53 +0200, Jiri Kosina wrote:
> On Sun, 10 Jun 2018, Srinivas Pandruvada wrote:
> > From: Even Xu <even.xu@xxxxxxxxx>
> >
> > Current ish driver only register resume/suspend PM callbacks which
> > don't support hibernation (suspend to disk). Now use the
> > SIMPLE_DEV_PM_OPS() MACRO instead of struct dev_pm_ops directly.
> > The suspend and resume functions will now be used for both suspend
> > to RAM and hibernation.
> >
> > If power management is disable, SIMPLE_DEV_PM_OPS will do nothing,
> > the suspend and resume related functions won't be used, so mark
> > them
> > as __maybe_unused to clarify that this is intended behavior, and
> > remove #ifdefs for power management.
> This describes details the patch does on code level, but what are the
> user
> observable effects? Hibernation resume doesn't fail any more?
> Hibernation
> is possible (and wasn't before)? Did kernel crash while trying to
> hibernate and this is the fix? Or ... ?
Can you add more details and resubmit ASAP?

Basically after hiberation, the ISH can't resume properly and user may
not see sensor events (for example: screen rotation may not work).
User will not see a crash or panic or anything except the following
message in log:
hid-sensor-hub 001F:8086:22D8.0001: timeout waiting for response from
ISHTP device

So this is adding support for S4/hiberbation to ISH.


> Thanks,