[PATCH 19/38] drm/hisilicon: Implement some semblance of vblank event handling

[Daniel Vetter]

On Tue, Jun 21, 2016 at 3:32 AM, Xinliang Liu <xinliang.liu at linaro.org> wrote:
> My understanding is that drm_crtc_arm_vblank_event work together with
> drm_crtc_handle_vblank (called in vblank interrupt).
> Arm the event first in somewhere(like atomic_begin/flush) and then
> send it out throuth drm_crtc_handle_vblank in vblank interrupt.
> In the other way, drm_crtc_send_vblank_event work together with flip
> interrupt. That's means event will be sent in flip interrupt
> immediately.
> Is this right?

First part is right. Second part about drm_crtc_send_vblank event just
sends out the vblank directly (using the last recorded vblank). The
vblank subsystem doesn't itself interact with any interrupt.

Note that there's kerneldoc for all of this. Please make sure it does
describe things sufficiently well, and if not please send in patches
to improve them.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch