On Fri, Jun 10, 2016 at 11:52:48AM -0500, Andy Gross wrote: [...] > > (1) enter_freeze() hooks are not strictly necessary to enable > > suspend-to-idle (they are if we want the tick to be frozen > > on suspend-to-idle, which is different) > > I'd think that you'd want the tick frozen. Even if you are going to > just call the deepest freezable idle state in your freeze_function, > you don't want to keep getting woken up as this costs some power usage As I said, that's a separate issue from these bindings. > > (2) If I understand your code correctly you have to set the suspend > > ops hook to make sure suspend-to-idle is enabled. This is a core > > code issue rather than anything else, given that suspend-to-idle > > (hey it is based on CPUidle !) does NOT rely on suspend ops to > > function. > > It only requires having suspend_ops and a valid function. Otherwise > you can never suspend and never exercise the freeze portion of the > cpuidle code. As I said, *currently* you have to call suspend_set_ops() to set up the pm_states label for PM_SUSPEND_FREEZE, suspend_ops are irrelevant to make suspend-to-idle work and as I said that's related to core code rather than platform specific suspend ops. We should solve issues, not work around them. > > So the gist is: as far as I am concerned you do not need any of this > > code to enable (yes you need PSCI idle states but no > > qcom,idle-state-spc compatible string whatsoever) suspend-to-idle > > on ARM64 on top of PSCI, let me know what I am missing. > > If we had the facilities in the arm cpuidle driver then for 64 bit > processors, I wouldn't have to do anything except provision my > suspend_ops + valid function. For 32 bit, we actually already use > this compat tag and I just have to add code in the spm driver (qcom > cpuidle) to init the suspend_ops. For 64-bit you do not have to have add any facility. 1) we should change core code to make PM_SUSPEND_FREEZE independent of suspend_set_ops() 2) we should define which idle states are freezable (99% of them are minus coupled idle states), through generic bindings Lorenzo -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
