On Fri, 11 Jun 2010, Mark Brown wrote: > On Fri, Jun 11, 2010 at 10:46:27AM -0400, Alan Stern wrote: > > On Fri, 11 Jun 2010, James Bottomley wrote: > > > > The one thing that does look difficult is that these power constraints > > > are device (and sometimes SoC) specific. Expressing them in a generic > > > way for the cpu govenors to make sense of might be hard. > > > Doesn't the clock framework already handle this sort of thing? > > The clock framework is implemented independantly for each CPU.
That's not an impediment, since drivers' requirements regarding which clocks remain running in which power states are necessarily platform-dependent also. On Fri, 11 Jun 2010, James Bottomley wrote: > Well, there are two elements to "this sort of thing": > > 1. Allow a driver to request that a given clock not be turned off. > 2. Make the cpuidle governors aware of a pending "don't turn off X > clock source" so they can keep the system in a state where the > clock doesn't get powered down. > > As far as I can tell from the code, neither currently exists at the > moment. Well then, can (or should) the clock framework interact with the pm-qos subsystem so that drivers don't have to worry about it? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
