Thanks Mark,

If your driver is not responding promptly to requests to terminate playback then an

underrun doesn't seem surprising.

Sometimes in my driver write calls doesn't return causing application to block forever and CPU pegged problem. Situation:Recording going on->go to sleep->come back from sleep->start recording again->try recording and playing back simultaneously(something like recording going on in background and you try to play short audio).

This causes write call to get blocked in playback case causing application to hangup. This doesn't happen if we don't go to sleep. So i think somewhere there is some problem with suspend->resume case which is difficult to figure out. I checked driver logs after coming back from sleep.I found for some time interrupts are coming then stopped coming suddenly So now after waking up i am reopening the playback device before opening the record device.Which has fixed the problem but not the root cause.