[Intel-gfx] Fighting tearing

[Chris Wilson]

On Sun, 09 Sep 2012 10:55:46 -0700, Ben Widawsky <ben at bwidawsk.net> wrote:
> On 2012-09-09 08:48, Roberth Sjonøy wrote:
> > Hello
> >
> > I run Arch Linux, with it's latest x.org and kernel, and I have
> > compiled libdrm and the intel driver from git, and I update it today.
> >
> > Buit this is issue exists even with the releases.
> >
> > WIth UXA, rendering of the windows in my XFCE4-desktop goes just
> > fines, good performance, windows (exspecially GTK+) doesn't hang 
> > after
> > if I drag them over the screen, but there is lot of small tearing.
> > And I want this to go away, I do not use any kind of composition, and
> > I am using XFCEs window manager.
> >
> > Here is my xorg.conf
> >
> >
> > Section "ServerFlags"
> >     Option "AutoAddDevices" "Off"
> > EndSection
> >
> > Section "InputDevice"
> >     Identifier     "Keyboard0"
> >     Driver         "keyboard"
> >     Option         "XkbLayout" "no"
> > EndSection
> >
> > Section "Device"
> >     Identifier  "Card0"
> >     Driver      "intel"
> >     Option      "AccelMethod" "UXA"
> >     Option      "TearFree" "true"
> >     Option      "MigrationHeuristic" "greedy"
> >     Option	"TripleBuffer" "true"
> > EndSection
> >
> > With SNA, the performance of the applications is muc much worse. If I
> > just replace UXA with SNA.
> >
> > Thanks in advance for any help.
> >
> > Regards,
> >
> > Roberth Sjonøy0
> 
> Unfortunately it's often the case that tearing is pretty much 
> unavoidable without a compositor. AFAIK you'd just be getting lucky with 
> SNA, as opposed to UXA.

Not so. He is explicitly asking for slow tear-free rendering with
Option "TearFree" "true". On my machines that takes about a 50%
performance hit which suggests pebkac which is reinforced by the lack
of information.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre