suspend() is called?

[Dan Williams]

On Tue, 2011-12-06 at 11:50 -0800, hong zhang wrote:
> List,
> 
> Can anyone explain how suspend() is called in driver or in which condition it will be executed?

suspend() gets called by the core kernel Power Management code when a
request from userspace (or somewhere else in the kernel) is sent.
That's pushed down to each bus (ie, USB, SPI, SDIO, PCI, etc) and each
bus type's core code handles suspending the individual devices.
acpitool is unlikely to help much here, instead you want to enable some
verbose debugging of the kernel's PM subsystem to figure out where the
request is coming from.  One common trigger is /sys/power/state.

Dan