On Fri, 09 Aug 2013 10:32:40 +0200, Tomasz Figa wrote: > On Friday 09 of August 2013 16:49:43 Cho KyongHo wrote: > > On Fri, 09 Aug 2013 01:03:05 +0200, Tomasz Figa wrote: > > > Hi KyongHo, > > > > > > nit: Please drop the trailing dot at the end of patch subject. > > > > Oh. I didn't catch that. > > Thank you. > > > > > On Thursday 08 of August 2013 18:41:17 Cho KyongHo wrote: > > > > This adds support for Advance Power Management and Runtime Power > > > > Management. > > > > > > This patch adds support for system-wide and runtime power management. > > > > Ok. > > > > > > Since System MMU is located in the same local power domain of its > > > > master H/W, System MMU must be initialized before it is working if > > > > its power domain was ever turned off. TLB invalidation according to > > > > unmapping on page tables must also be performed while power domain > > > > is > > > > turned on. > > > > > > > > This patch ensures that resume and runtime_resume(restore_state) > > > > functions in this driver is called before the calls to resume and > > > > runtime_resume callback functions in the drivers of master H/Ws. > > > > Likewise, suspend and runtime_suspend(save_state) functions in this > > > > driver is called after the calls to suspend and runtime_suspend in > > > > the > > > > drivers of master H/Ws. > > > > > > > > In order to get benefit of this support, the master H/W and its > > > > System > > > > MMU must resides in the same power domain in terms of Linux kernel. > > > > If > > > > a master H/W does not use generic I/O power domain, its driver must > > > > call iommu_attach_device() after its local power domain is turned > > > > on, > > > > iommu_detach_device before turned off. > > > > > > I don't get the point of this last paragraph. What a power domain can > > > be in other terms? Is there any other way to support power domains on > > > Exynos than generic power domains? > > > > I just addressed the case a device driver turns off local power of its > > device without the help of generic I/O powerdomain. > > Out of curiosity, do we have such cases for Exynos in mainline kernel? > IMHO this is what the generic PM core is for and drivers shouldn't care > about such low level PM details. I don't know if there is the case and I also agree with you. I hope that there is no case that I addressed. I just mentioned an exceptional case. The best way is that all device drivers of master H/W of System MMU register their defvice in a generic i/o powerdomain. Thank you. KyongHo. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
