fb_defio: add first_io callback
From: Heiko Stuebner <heiko@...> Date: Fri, 30 Dec 2011 23:16:19 +0100
Commit-Message
With this optional callback the driver is notified when the first page is entered into the pagelist and a new deferred_io call is scheduled. A possible use-case for this is runtime-pm. In the first_io call pm_runtime_get() could be called, which starts an asynchronous runtime_resume of the device. In the deferred_io callback a call to pm_runtime_barrier() makes the sure, the device is resumed by then and a pm_runtime_put() may put the device back to sleep. Also, some SoCs may use the runtime-pm system to determine if they are able to enter deeper idle states. Therefore it is necessary to keep the use-count from the first written page until the conclusion of the screen update, to prevent the system from going to sleep before completing the pending update. Signed-off-by: Heiko Stuebner <heiko@...>
Patch-Comment
drivers/video/fb_defio.c | 4 ++++ include/linux/fb.h | 1 + 2 files changed, 5 insertions(+), 0 deletions(-)
Statistics
- 5 lines added
- 0 lines removed