[maemo-developers] SDL, tearing, X overhead and direct framebuffer gfx

[From: Siarhei Siamashka]

On Feb 18, 2008 1:28 PM, Tapani Pälli <tapani.palli at nokia.com> wrote:
> > Could you please verify and confirm this information? Framebuffer
> > driver from OS2007 supported tearsync (via OMAPFB_FORMAT_FLAG_TEARSYNC
> > flag as Frantisek mentioned), and it was used at least for video.
> > Well, I have noticed some tearing in mplayer with OS2008 though.
> >
> This is what I've heard from our kernel team members, maybe they could
> share some more light to this. AFAIK the hardware itself does not offer
> sync.

Is it possible to invite kernel team members to join this discussion?
:) At least it would be nice if they had a look at this thread.

N800 hardware definitely supports tearsync. It worked fine in OS2007
(I'm not telling that OS2008 does not support it anymore, I just can't
check this till I get home). When I looked through xserver sources
last time, tearsync was used for video planes, but was disabled for
normal rgb updates. This can be easily explained. Video usually has
lower resolution than 800x480, requires less graphics bandwidth and it
is possible to display it with perfect tearsync. With tearsync enabled
for rgb updates, we get an ugly tearing line at a fixed location in
the bottom of screen when doing 800x480 rgb update (the first OS2008
firmware had this problem btw). Without tearsync flag set, we also get
tearing, but at random locations on screen, and it is less
noticeable/annoying.