Re: [AD] vsync and SVGAlib (was Problems: Grabber and windowing)

[Eric Botcazou <ebotcazou@xxxxxxxxxx>]

>    Good stuff, that patch will work. Indeed the demo was flickering with
> me as well (sorry didn't get back to your first message... busy with
> school). This patch will certainly fix all those problems I was noticing
> as well.

Hopefully.

>   However, have you all concluded that documentation on the
> show_video_bitmap & request_video_bitmap is sufficient? I still think it
> is misleading because request_video_bitmap states "rather than waiting for
> a retrace" which seems like it would have the opposite behavior of
> show_video_bitmap (which, apparently, doesn't necessarily have to wait on
> vsync either).

But it has the opposite behavior: show_video_bitmap()/scroll_screen() are 
used for page flipping and _must_ both wait for the vertical retrace, while 
request_video_bitmap()/request_scroll() are used for triple buffering and 
_must_ both not wait for the vertical retrace (otherwise, triple buffering 
is not supported).

> Maybe I'm the only one getting those confused, but if show_video_bitmap
> doesn't really have to wait for vsync maybe it should be more obvious
> because I would have certainly thought it would from the docs.

If show_video_bitmap() doesn't wait for the vsync, it's a bug, period.

-- 
Eric Botcazou