On Tue, 1 Oct 2013, yoma sophian wrote:
> hi all:
> >>
> >>> >> When we use "echo mem > /sys/power/state" , we didn't see any function
> >>> >
> >>> > "mem" is a kind of sleep, not a kind of hibernation.
> >>> But I don't see any usb sleep funciton called from log
> >>
> >> What messages do you expect to see?
> > When I try the command yesterday, I didn't plug in usb dick. :)
> > I attach the log after I plug in usb stick.
> from the log, I conclude calling path as below:
> 1. calling dev_pm_ops
> 2. calling interface driver's suspend
> 3. calling usb device's suspend.
That's right.
> My questions are:
> 1. in dev_pm_ops, we use same function, usb_suspend, but different
> pm_message to tell different kind of power management.
Yes.
> 2. but in usb device's suspend, generic_suspend, different pm_message
> seems has the same effect.
Not true. generic_suspend() does this:
/* Non-root devices don't need to do anything for FREEZE or PRETHAW */
else if (msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_PRETHAW)
rc = 0;
else
rc = usb_port_suspend(udev, msg);
The FREEZE and PRETHAW events are treated differently from the others.
> 3. is there any platform apis in generic_suspend for us to register
> when we try to handle hw's specific behavior during hibernate/restore?
No. What specific behavior do you want to handle?
Alan Stern
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