Messages in this thread |  | | | Date | Tue, 26 Jun 2012 10:30:06 -0400 (EDT) | | From | Alan Stern <> | | Subject | Re: pm runtime and system suspend resume |
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On Tue, 26 Jun 2012, chao xie wrote:
> If we want to separate clocks off and phy off, what should we do?
Why do you want to separate them?
The Runtime PM framework doesn't have any notion of multiple low-power states. It recognizes only two possibilities: active and suspended.
If turning the clocks on and off is very quick, you can simply have the driver turn them on before each I/O operation and turn them off when the operation is finished.
> in fact, in the driver, at some time, it can shutdown clock, and at > some time, it can shut down phy too. So what i want to do it make > runtime_idle to shut down the clocks while in runtime_suspend to > shutdown the clocks and phy.
The runtime_idle routine is not supposed to turn anything off. All it should do is decide whether or not to call pm_runtime_suspend. The actual work of turning things on and off belongs in the driver's (or subsystem's or PM domain's) runtime_resume and runtime_suspend routines.
> So when the driver is in idle, and i can call pm_runtime_put which > will call runtime_idle to shutdown the clocks, while when the driver > want to turn off phy, it means it will enter deeper idle, so i need > call pm_runtime_put_sync_suspend.
You can do that if you want, but it is not how the Runtime PM framework was intended to work. Instead of calling pm_runtime_put, why not just turn off the clocks?
Or why not turn off the clocks at the same time as the phy?
> The question is if when driver calls pm_runtime_put_sync_suspend, the > driver has already called pm_runtime_put, the usaga_count is 0 now, so > driver has to call pm_runtime_get and then call > pm_runtime_put_sync_suspend.
If you know the usage count is 0 already, you can just call pm_runtime_suspend directly.
> PM runtime provide runtime_idle and runtime_suspend, but the device > status has only two kinds of status, active or no-active. It confuses > me.
Idle means "the device is active but the usage count is 0". The purpose of the runtime_idle callback is to let your driver know that it can start a suspend if it wants to.
> It means that the pm runtime can not support multiple level of > power mode for device.
That's right.
> actually, i think it has provided two kinds of > callback runtime_idle and runtime_suspend, and it should maintain at > least 3 state, idle, suspend, active for the device.
No, that's not how it was designed.
Alan Stern
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