On Thu, Oct 28, 2010 at 9:43 PM, Nicolas Pitre <nico@xxxxxxxxxxx> wrote: > On Thu, 28 Oct 2010, Ohad Ben-Cohen wrote: > >> On Thu, Oct 28, 2010 at 5:39 PM, Kishore Kadiyala >> <kishorek.kadiyala@xxxxxxxxx> wrote: >> > Wouldn't adapting the host driver just to PM-Runtime will answer the >> > above issues? >> >> It's not enough. >> >> When the card is runtime suspended, sure, the host controller will >> immediately get idle notification by runtime PM core. >> >> But you may still want to gate the clock to the host controller on bus >> inactivity, even if the card is not runtime suspended. The decision to >> do this should come from the mmc core. > > This is not clear that this is something that the core can effectively > help with. Opportunistic power saving at the host controller level is > pretty much hardware dependent and may wildly vary in capabilities... > and bugs. So in this later case I think the driver for the host > controller is the best place to just set up a timer and gate the clock > after a certain period of inactivity for example. Agree, So briefly, calling pm_runtime_put_sync using a activity based timer in the host Controller driver will gate the clock to the controller . On idle notification to PM runtime core, which will trigger a call to the runtime_suspend hook in bus.c [https://patchwork.kernel.org/patch/226671/ ] which will perform powering off the Card Regards, Kishore -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
