Jon Hunter <jon-hunter@xxxxxx> writes: > On 05/08/2012 11:18 AM, Kevin Hilman wrote: >> "Cousson, Benoit" <b-cousson@xxxxxx> writes: >> >>> On 5/8/2012 4:00 PM, Kevin Hilman wrote: >>>> Jean Pihet<jean.pihet@xxxxxxxxxxxxxx> writes: >>>> >>>> [...] >>>> >>>>>>>> Yes, indeed, we should not hack the flags to fix that kind of issue. The >>>>>>>> flags describe what the HW is capable of, and the EMU CD can support >>>>>>>> HW_AUTO >>>>>>>> and SW_WAKEUP. AFAIK, the issue with that EMU CD is that the only valid >>>>>>>> next >>>>>>>> power state is OFF, meaning that no retention mode is supported. So any >>>>>>>> transition to idle will go to OFF and lead to a reset upon wakeup. >>>>>>>> >>>>>>>> That being said, being able to transition to OFF during idle is a >>>>>>>> perfectly >>>>>>>> valid state for most powerdomain in OMAP anyway, so we should be able to >>>>>>>> restore from OFF mode smoothly. >>>>>>>> >>>>>>>> It looks to me that what is missing here is *just* a restore path in the >>>>>>>> PMU/CTI code. But I'm probably missing some nasty details in this issue >>>>>>>> :-) >>>>>>> >>>>>>> Although it is perfectly feasible to have a seamless transition of the >>>>>>> EMU power domain, I think the PMU counters will not be accurate >>>>>>> anymore since they stop counting events when going to OFF and re-start >>>>>>> after the state restore. >>>>>> >>>>>> >>>>>> Good point, but I think the PMU might still works fine because located >>>>>> inside the MPU domain. AFAIR, only the path to access the PMU and the CTI is >>>>>> going to OFF and thus will be reset. >>>>> >>>>> Ever better point ;p Thanks for the precision. >>>>> In any case my point was: can we allow the EMU CD to go OFF or prevent >>>>> it from doing so? We need to answer that question first. >>>>> >>>> >>>> The idea I've suggested is to use runtime PM for this. As long as the >>>> PMU is in use, it will be runtime PM enabled (and not allowed to go into >>>> HWSUP idle.) When it is not used, it will be allowed to HWSUP idle, and >>>> then be reset. The next time it is needed, the runtime resume will need >>>> to do a full re-init. >>> >>> Oh, but does that mean that this driver is not pm_runtime adapted yet? >>> >> >> Actually, it is. Ming Lei has done it. >> >> Currently, Will has collected this[1] and is waiting (patiently) for us >> to produce a real fix that doesn't kill PM in the process. > > I had to make a couple mods to Ming's patches but I do have something > working now that _should_ not break PM. However, per my previous email > (in response to Benoit's) I am struggling with the definition of the > CLKDM_CAN_XXXXXX_AUTO flags to know the correct way to fix this. > > I was going to send out my patches, but I wanted to get some more > feedback on this first. While waiting for feeback, if you set the flags to CAN_FORCE_WAKEUP and CAN_HWSUP, can you get the PMU interrupts working after an EMU CD idle transition (and reset.) Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
