Re: Issue with i2c-designware-platdrv's suspend/runtime-suspend handling

[Jarkko Nikula]

On 01/31/2017 12:05 AM, John Stultz wrote:
> On Tue, Jan 24, 2017 at 2:03 PM, John Stultz <john.stultz@xxxxxxxxxx> wrote:
> > Doing some further debugging, it seems the problem is that the device
> > is being runtime suspended, and then at suspend time, we're calling
> > the same logic, calling i2c_dw_plat_prepare_clk, which causes the clk
> > count warning.
> >
> > Removing the runtime pm ops:
> > -       SET_RUNTIME_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume, NULL)
> > +//     SET_RUNTIME_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume, NULL)
> >
> > seems to avoid the warning, but clearly isn't ideal. :)
> >
> > Should there be some logic keep track of the suspend state for the
> > dw_i2c_dev device so we don't try to suspend (or resume) it twice?  Or
> > is there something else I'm missing to keep this from happening?
>
> Ping? Any thoughts on how best to fix this?  I'm leaning towards
> adding a suspended state to the struct dw_i2c_dev. Any objections?
I wonder why device PM doesn't take care of this?

If i2c-designware is enumerated from ACPI then drivers/acpi/device_pm.c: 
acpi_subsys_suspend() resumes devices suspended at run time before 
system suspend so dw_i2c_plat_suspend() won't be called twice.

But still I think device PM should not attempt to suspend already 
suspended device?

--
Jarkko