This allows ddx to set swap_limit if there is more than one back
buffer for drawable. Setting swap_limit has to also check if change
affects a client that is blocked.
This can be used to implement N-buffering in driver with minimal
logic in allocation and selecting next back.
Signed-off-by: Pauli Nieminen <ext-pauli.nieminen@nokia.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Reviewed-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Keith Packard <keithp@keithp.com>