Re: S3 resume regression [1cf4f629d9d2 ("cpu/hotplug: Move online calls to hotplugged cpu")]

[Rafael J. Wysocki]

On 5/16/2016 9:39 PM, Ville Syrjälä wrote:
> On Wed, May 11, 2016 at 04:34:06PM +0300, Ville Syrjälä wrote:
> > On Wed, May 11, 2016 at 08:44:45AM -0400, Steven Rostedt wrote:
> > > On Wed, 11 May 2016 15:21:16 +0300
> > > Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote:
> > >
> > > > Yeah can't get anything from the machine at that point. netconsole
> > > > didn't help either, and no serial on this machine. And IIRC I've
> > > > tried ramoops on this thing in the past but unfortunately the memory
> > > > got cleared on reboot.
> > > Can you look at the documentation in the kernel code at
> > >
> > > Documentation/power/basic-pm-debugging.txt And follow the procedures
> > > for testing suspend to RAM (although it requires mostly running the
> > > same tests as for hibernation suspending).
> > >
> > > You can also use the tool s2ram for this as well.
> > >
> > > See Documentation/power/s2ram.txt
> > >
> > > Perhaps this can give us a bit more light onto the problem.
> > >
> > > Basically the above does partial suspend and resume, and can pinpoint
> > > problem areas down to a more select location.
> > All the pm_test modes work fine. The only difference between them was
> > that 'platform' required me to manually wake up the machine (hitting a
> > key was sufficient), whereas the others woke up without help.
> >
> > pm_trace gave me
> > [    1.306633]   Magic number: 0:185:178
> > [    1.322880]   hash matches ../drivers/base/power/main.c:1070
> > [    1.339270] acpi device:0e: hash matches
> > [    1.355414]  platform: hash matches
> >
> > which is the TRACE_SUSPEND in __device_suspend_noirq(), so no help
> > there.
> >
> > I guess I could try to sprinkle more TRACE_RESUMEs around into some
> > early resume code. If anyone has good ideas where to put them it
> > might speed things up a bit.
> So I did a bunch of that and found that it gets stuck somewhere
> around executing the _WAK method:
> platform_resume_noirq
>   acpi_pm_finish
>    acpi_leave_sleep_state
>     acpi_hw_sleep_dispatch
>      acpi_hw_legacy_wake
>       acpi_hw_execute_sleep_method
>        acpi_evaluate_object
>         acpi_ns_evaluate
>          acpi_ps_execute_method
>           acpi_ps_parse_aml
>
> It also seesm that adding a few TRACE_RESUME()s or an msleep() right
> after enable_nonboot_cpus() can avoid the hang, sometimes.
>
> I've attached the DSDT in case anyone is interested in looking at it.

What if you comment out the execution of _WAK (line 318 of 
drivers/acpi/acpica/hwsleep.c in 4.6)?  Does that make any difference?