In my application a no. of devices (camera, A/D, D/A etc ) are communicating with a server. I have two options for saving power consumptions in a device as not all devices has to work always:
1- Do poling, i.e each device periodically keep on looking at a content of a file where it gets a value for wake or sleep. If it finds wake, then it wakes up and does its job.
In this case actually the device will be sleeping but the driver will be active and poling.
2- Using interrupts, I can awake a device when needed.
I am not able to decide which way to go and why. Can someone please enlighten me in this regard?
Platform: Windows 7, 32 bit, running on Intel Core2Duo
Polling is imprecise by its nature. The higher your target precision gets, the more wasteful the polling becomes. Ideally, you should consider polling only if you cannot do something with interrupts; otherwise, using an interrupt should be preferred.
One exception to this rule is if you would like to “throttle” something intentionally, for example, when you may get several events per second, but you would like to react to only one event per minute. In such cases you often use a combination of polling and interrupts, where an interrupt sets a flag, and polling does the real job, but only when the flag is set.