On Tue, Dec 18, 2012 at 03:31:01AM +0100, Joseph Lo wrote: > The "powered-down" cpuidle mode of Tegra20 needs the CPU0 be the last one > core to go into this mode before other core. The coupled cpuidle framework > can help to sync the MPCore to coupled state then go into "powered-down" > idle mode together. The driver can just assume the MPCore come into > "powered-down" mode at the same time. No need to take care if the CPU_0 > goes into this mode along and only can put it into safe idle mode (WFI). > > The powered-down state of Tegra20 requires power gating both CPU cores. > When the secondary CPU requests to enter powered-down state, it saves > its own contexts and then enters WFI for waiting CPU0 in the same state. > When the CPU0 requests powered-down state, it attempts to put the secondary > CPU into reset to prevent it from waking up. Then power down both CPUs > together and power off the cpu rail. > > Be aware of that, you may see the legacy power state "LP2" in the code > which is exactly the same meaning of "CPU power down". > > Based on the work by: > Colin Cross <ccross@xxxxxxxxxxx> > Gary King <gking@xxxxxxxxxx> > > Signed-off-by: Joseph Lo <josephl@xxxxxxxxxx> > --- > V3: > * sqash last two patch in previous version to support coupled cpuidle > directly nitpick - it should be 'squash'. Cheers, Peter. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
