[Intel-gfx] Tearing video on Sandy Bridge

[Daniel Vetter]

On Thu, May 03, 2012 at 08:09:09PM +0200, tino.keitel+xorg at tikei.de wrote:
> Hi,
> 
> the tearing video issue with XV output seemed to be fixed on my old
> computer with i945 graphics at some point. Last year I upgraded to a
> box with i5-2400, and got bitten again by tearing video. Currently I
> use kernel 3.4-rc5, Xserver 1.12 and xorg-intel 2.18. I use gnome3 and
> gnome-shell on my desktop, and tried several players (mplayer, vlc,
> mythtv).
> 
> Am I just doing something wrong, or is smooth video playback not the
> scope of the Sandy Bridge development?

We used scanline waits embedded in the gpu command stream to achieve
tear-free video. On snb hw designers killed that feature :(

The only way to get tear-free screen updates on snb is with pageflips,
which requires a opengl compositor (and wayland if you have more than one
screen).
-Daniel
-- 
Daniel Vetter
Mail: daniel at ffwll.ch
Mobile: +41 (0)79 365 57 48