On 8 May 2014 13:44, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > On Thursday, May 08, 2014 12:59:20 PM Ulf Hansson wrote: >> On 8 May 2014 12:53, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: >> > On Thursday, May 08, 2014 09:49:36 AM Ulf Hansson wrote: >> >> On 8 May 2014 01:29, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: >> >> > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> >> >> > >> >> > Currently, some subsystems (e.g. PCI and the ACPI PM domain) have to >> >> > resume all runtime-suspended devices during system suspend, mostly >> >> > because those devices may need to be reprogrammed due to different >> >> > wakeup settings for system sleep and for runtime PM. >> >> > >> >> > For some devices, though, it's OK to remain in runtime suspend >> >> > throughout a complete system suspend/resume cycle (if the device was in >> >> > runtime suspend at the start of the cycle). We would like to do this >> >> > whenever possible, to avoid the overhead of extra power-up and power-down >> >> > events. >> >> > >> >> > However, problems may arise because the device's descendants may require >> >> > it to be at full power at various points during the cycle. Therefore the >> >> > most straightforward way to do this safely is if the device and all its >> >> > descendants can remain runtime suspended until the resume stage of system >> >> > resume. >> >> > >> >> > To this end, introduce dev->power.leave_runtime_suspended. >> >> > If a subsystem or driver sets this flag during the ->prepare() callback, >> >> > and if the flag is set in all of the device's descendants, and if the >> >> > device is still in runtime suspend at the beginning of the ->suspend() >> >> > callback, that callback is allowed to return 0 without clearing >> >> > power.leave_runtime_suspended and without changing the state of the >> >> > device, unless the current state of the device is not appropriate for >> >> > the upcoming system sleep state (for example, the device is supposed to >> >> > wake up the system from that state and its current wakeup settings are >> >> > not suitable for that). Then, the PM core will not invoke the device's >> >> > ->suspend_late(), ->suspend_irq(), ->resume_irq(), ->resume_early(), or >> >> > ->resume() callbacks. Instead, it will invoke ->runtime_resume() during >> >> > the device resume stage of system resume. >> >> > >> >> > By leaving this flag set after ->suspend(), a driver or subsystem tells >> >> > the PM core that the device is runtime suspended, it is in a suitable >> >> > state for system suspend (for example, the wakeup setting does not >> >> > need to be changed), and it does not need to return to full >> >> > power until the resume stage. >> >> > >> >> > Changelog based on an Alan Stern's description of the idea >> >> > (http://marc.info/?l=linux-pm&m=139940466625569&w=2). >> >> > >> >> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> >> >> > --- >> >> > drivers/base/power/main.c | 31 ++++++++++++++++++++++++------- >> >> > drivers/base/power/runtime.c | 10 ++++++++++ >> >> > include/linux/pm.h | 3 +++ >> >> > include/linux/pm_runtime.h | 16 ++++++++++++++++ >> >> > kernel/power/Kconfig | 4 ++++ >> >> > 5 files changed, 57 insertions(+), 7 deletions(-) >> >> > >> >> > Index: linux-pm/kernel/power/Kconfig >> >> > =================================================================== >> >> > --- linux-pm.orig/kernel/power/Kconfig >> >> > +++ linux-pm/kernel/power/Kconfig >> >> > @@ -147,6 +147,10 @@ config PM >> >> > def_bool y >> >> > depends on PM_SLEEP || PM_RUNTIME >> >> > >> >> > +config PM_BOTH >> >> > + def_bool y >> >> > + depends on PM_SLEEP && PM_RUNTIME >> >> > + >> >> >> >> Should we not depend on PM_RUNTIME only? Thus we don't need the new >> >> Kconfig, >> > >> > Well, OK. I guess we can tolerate one useless statement in rpm_resume() >> > in case CONFIG_PM_SLEEP is unset. >> > >> >> and then we could rename the new APIs to pm_runtime_* instead. >> > >> > That would just make the name longer - for what value? >> >> Only "__set_leave_runtime_suspended" will be a bit longer. >> >> The idea I had was to clearly indicate, these functions is a part of >> PM_RUNTIME API. >> >> Compare what you have: >> __set_leave_runtime_suspended >> pm_set_leave_runtime_suspended >> pm_leave_runtime_suspended >> >> To what I suggest: >> __pm_runtime_set_leave_suspended >> pm_runtime_set_leave_suspended >> pm_runtime_leave_suspended > > And why exactly do you think these are any better? Because that's how all (almost all) other functions in the runtime PM API are specified - I believe it makes sense to keep them aligned. Anyway, if you insist in keeping your functions names, it's not that of a big deal for me. Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > > The flag is not called leave_suspended surely? To me that doesn't matter, the flag has nothing to do with the function names in an API. > > > -- > I speak only for myself. > Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
