Batch mode will send multiple task to kernel at one time. And its
non-block poll is triggered by timer and looper.
This mode will reduce the ioctl overhead on ultra multi-instance case.
Main features and some notes:
1. Each client type has independence batch server.
2. Each mpp_device can attach or not attach to server independently.
3. When a device is attached to server all its tasks will be sent to
kernel through the server session not original client session.
4. The tasks are sent non-block and wait in block or non-block.
5. The batch mode can only be switch on/off when hardware is not
working.
Change-Id: I07462d852cb002259d2873e13c12f6f8a489ba8e
Signed-off-by: Herman Chen <herman.chen@rock-chips.com>
