[POWERPC] hvc_console: Polling mode timer backoff

#define HVC_MAJOR	229

#define HVC_MINOR	0

#define TIMEOUT		(10)

/*

 * Wait this long per iteration while trying to push buffered data to the

 * hypervisor before allowing the tty to complete a close operation.

	return hp->n_outbuf;

}

/*

 * timeout will vary between the MIN and MAX values defined here.  By default

 * and during console activity we will use a default MIN_TIMEOUT of 10.  When

 * the console is idle, we increase the timeout value on each pass through

 * msleep until we reach the max.  This may be noticeable as a brief (average

 * one second) delay on the console before the console responds to input when

 * there has been no input for some time.

 */

#define MIN_TIMEOUT		(10)

#define MAX_TIMEOUT		(2000)

static u32 timeout = MIN_TIMEOUT;

#define HVC_POLL_READ	0x00000001

#define HVC_POLL_WRITE	0x00000002

 bail:

	spin_unlock_irqrestore(&hp->lock, flags);

	if (read_total)

	if (read_total) {

		/* Activity is occurring, so reset the polling backoff value to

		   a minimum for performance. */

		timeout = MIN_TIMEOUT;

		tty_flip_buffer_push(tty);

	}

	return poll_mask;

}

		if (!hvc_kicked) {

			if (poll_mask == 0)

				schedule();

			else

				msleep_interruptible(TIMEOUT);

			else {

				if (timeout < MAX_TIMEOUT)

					timeout += (timeout >> 6) + 1;

				msleep_interruptible(timeout);

			}

		}

		__set_current_state(TASK_RUNNING);

	} while (!kthread_should_stop());