[PATCH 1/2] drm/udl: make page flips asynchronous.

[Haixia Shi]

On Thu, Mar 5, 2015 at 2:33 AM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Wed, Mar 04, 2015 at 06:26:23PM -0800, Haixia Shi wrote:
>> This also limits the maximum frequency of page flips by the vrefresh rate.
>>
>> Signed-off-by: Haixia Shi <hshi at chromium.org>
>> Reviewed-by: Stéphane Marchesin <marcheu at chromium.org>
>> Tested-by: Haixia Shi <hshi at chromium.org>
>
> I think the better approach would have been to push the task down to
> udl_handle_damage(). Almost all of the callers would prefer deferred
> updates (with the notable exception of modesetting).
> -Chris

I'm not sure this is correct. While there's reasonable expectation for
page flips to be asynchronous (when flip completes it would send the
vblank event), my understanding is that fb_fillrect, fb_copyarea and
fb_imageblit are synchronous.

>
> --
> Chris Wilson, Intel Open Source Technology Centre