On Fri, 11 Jun 2010, James Bottomley wrote: > On Thu, 2010-06-10 at 21:21 -0700, David Brownell wrote: > > Do we at least have a clean way that a driver can > > reject a system suspend? I've lost track of many > > issues, but maybe this could be phrased as a QOS > > constraint: the current config of driver X needs > > clock Y active to enter the target system suspend > > state, driver's suspend() method reports as much. Then the entry to > > that system state gets blocked > > if the clock isn't enabled. > > So in QoS modifications to android patches, the answer is "yes" ... > except that the current android patch set didn't actually have this type > of wakelock in it. > > Android wants an idleness suspend block (or pm qos constraint) that a > driver can set to prevent the system idleness power govenor from > dropping into a power state too low for the driver, so in USB terms this > would prevent the states that shut down the clock. For android, it > prevented shutdown of an internal i2c bus. > > 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? Alan Stern _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
