Hello Soren, On Fri, Mar 01, 2013 at 06:51:26PM +0000, Soren Brinkmann wrote: > Enable the 'dynamic clock stop' and 'standby mode' features in the > l2x0 disable path. > > Signed-off-by: Soren Brinkmann <soren.brinkm...@xilinx.com> > --- > Hi, > > we are currently implementing a suspend to RAM like low power mode for > Zynq. > The code for entering suspend looks like this: > outer_disable(); > cpu_suspend(0, zynq_pm_suspend); > outer_resume(); > > In our low power guidelines we mention the pl310's standby and clock stop > feature and that they should be enabled for low power modes. The question > arising here now is: Does the outer_disable() make these features redundant, > or does it make sense to add it like shown in this patch?
The settings in the power control register are unrelated to CPU suspend afaict. Instead, they are for semi-autonomous entry to non-destructive low-power states (e.g. when the L2 is idle for n cycles, or all of the L1 masters have asserted WFI). This raises the question of whether or not we should poke this register at all (other than saving/restoring it across suspend, which *is* destructive). I personally think that this stuff is better off being dealt with in firmware and initialised there, which follows what we do for other registers like this. Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
