[PATCH 0/3] PM / ACPI / i2c: Runtime PM aware system sleep handling

[Rafael J. Wysocki]

On Tuesday, August 29, 2017 1:44:11 PM CEST Ulf Hansson wrote:
> On 29 August 2017 at 12:29, Johannes Stezenbach <js at sig21.net> wrote:
> > Hi,
> >
> > On Tue, Aug 29, 2017 at 02:18:13AM +0200, Rafael J. Wysocki wrote:
> >> On Wednesday, August 23, 2017 4:42:00 PM CEST Ulf Hansson wrote:
> >> > The i2c designware platform driver, drivers/i2c/busses/i2c-designware-platdrv.c,
> >> > isn't well optimized for system sleep.
> >> >
> >> > What makes this driver particularly interesting is because it's a cross-SoC
> >> > driver, which sometimes means there is an ACPI PM domain attached to the i2c
> >> > device and sometimes not. The driver is being used on both x86 and ARM.
> > ...
> >> Basically, the point is to allow i2c-designware-platdrv to point its late
> >> suspend and early resume callbacks, respectively, to pm_runtime_force_suspend()
> >> and pm_runtime_force_resume() which then will do the right thing regardless of
> >> whether or not the device is runtime suspended when system suspend starts.
> >
> > I'd like to point out a comment added by Hans de Goede in
> > https://bugzilla.kernel.org/show_bug.cgi?id=193891#c99
> >
> >   The D0 / D3 methods of some devices use ACPI OpRegions on the PMIC which is
> >   attached to I2C7, these methods get executed by acpi_dev_suspend_late /
> >   acpi_dev_resume_early. Since the i2c-designware driver uses regular suspend /
> >   resume callbacks it is already suspended at the time those calls happen,
> >   leading to a device-suspend error and the system not suspending at all.
> 
> Yes, that's why I moved those operation to be managed at the
> ->suspend_late() in my series, and at the same time prevent the
> direct_complete patch from executed for this device.
> 
> >
> > It's the reason for the Cherrytrail I2C7 special treatment in
> > i2c-designware-platdrv.c and pm_disabled = true in i2c-designware-baytrail.c,
> > however pm_disabled seems to be a problem for S0ix support.
> > To solve it, i2c-designware-platdrv needs to suspend after all
> > devices using ACPI OpRegions for suspend.
> >
> >
> > Johannes
> 
> Did you try out my series (v2) if that could fix this problem in a
> more flexible manner?
> 
> In other words, is it fine if the device remains runtime PM enabled
> during the entire device_suspend() phase, and also not being suspended
> until ->suspend_late()?

Ulf, please, this is a *different* problem.

Can we focus on one problem at a time?

Thanks,
Rafael