Re: [PATCH] drm/rockchip: Return -EBUSY if there's already a pending flip event v5

From: Daniel Stone
Date: Tue May 24 2016 - 03:34:58 EST

On 24 May 2016 at 09:27, Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx> wrote:
> As per the docs, atomic_commit should return -EBUSY "if an asycnhronous
> updated is requested and there is an earlier updated pending".
> v2: Use the status of the workqueue instead of vop->event, and don't add
> a superfluous wait on the workqueue.
> v3: Drop work_busy, as there's a sizeable delay when the worker
> finishes, which introduces a race in which the client has already
> received the last flip event but the next page flip ioctl will still
> return -EBUSY because work_busy returns outdated information.
> v4: Hold dev->event_lock while checking the VOP's event field as
> suggested by Daniel Stone.
> v5: Only block if there's outstanding work if it's a blocking call.
> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>

Reviewed-by: Daniel Stone <daniels@xxxxxxxxxxxxx>