[Intel-gfx] Fighting tearing

[Ben Widawsky]

On Mon, 10 Sep 2012 16:09:18 +0200
Roberth Sjonøy <roberth.sjonoy at gmail.com> wrote:

> With the WM I use (xfce WM 4.10.0) with it's compositor, the tearing
> is much less, but the little tearing who exist is very noticable.

Your option is SNA + TearFree, or use a real composited desktop. I know
it sucks. Or maybe complain to the XFCE guys to use real pageflips in their
compositor?

> 
> On Sun, Sep 9, 2012 at 8:00 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > 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



-- 
Ben Widawsky, Intel Open Source Technology Center