Tearing video on Sandy Bridge

Tearing video on Sandy Bridge

[tino.keitel+xorg]

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?

Regards,
Tino

Re: Tearing video on Sandy Bridge

[Daniel Vetter]

On Thu, May 03, 2012 at 08:09:09PM +0200, tino.keitel+xorg@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@ffwll.ch
Mobile: +41 (0)79 365 57 48

Re: Tearing video on Sandy Bridge

[Tino Keitel]

On Thu, May 03, 2012 at 20:43:01 +0200, Daniel Vetter wrote:

[...]

> The only way to get tear-free screen updates on snb is with pageflips,
> which requires a opengl compositor

Thanks. What do you mean with "opengl compositor"? Isn't the Gnome3
desktop providing this?

Regards,
Tino

Re: Tearing video on Sandy Bridge

[Daniel Vetter]

On Thu, May 03, 2012 at 09:34:28PM +0200, Tino Keitel wrote:
> On Thu, May 03, 2012 at 20:43:01 +0200, Daniel Vetter wrote:
> 
> [...]
> 
> > The only way to get tear-free screen updates on snb is with pageflips,
> > which requires a opengl compositor
> 
> Thanks. What do you mean with "opengl compositor"? Isn't the Gnome3
> desktop providing this?

Well, it needs to do vsync'ed updates, and to work correctly, the client
also needs to do dri2 buffer swaps. Dunno where to set the former in gnome
3, for the later try a opengl output plugin (or libva).
-Daniel
-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48

Re: Tearing video on Sandy Bridge

[tino.keitel+xorg]

On Thu, May 03, 2012 at 21:46:37 +0200, Daniel Vetter wrote:
> On Thu, May 03, 2012 at 09:34:28PM +0200, Tino Keitel wrote:
> > On Thu, May 03, 2012 at 20:43:01 +0200, Daniel Vetter wrote:
> > 
> > [...]
> > 
> > > The only way to get tear-free screen updates on snb is with pageflips,
> > > which requires a opengl compositor
> > 
> > Thanks. What do you mean with "opengl compositor"? Isn't the Gnome3
> > desktop providing this?
> 
> Well, it needs to do vsync'ed updates, and to work correctly, the client

Is this in the dri config file?

Regards,
Tino

Re: Tearing video on Sandy Bridge

[Chun-Yu Shei]

On 05/03/2012 03:51 PM, tino.keitel+xorg@tikei.de wrote:
> On Thu, May 03, 2012 at 21:46:37 +0200, Daniel Vetter wrote:
>> On Thu, May 03, 2012 at 09:34:28PM +0200, Tino Keitel wrote:
>>> On Thu, May 03, 2012 at 20:43:01 +0200, Daniel Vetter wrote:
>>>
>>> [...]
>>>
>>>> The only way to get tear-free screen updates on snb is with pageflips,
>>>> which requires a opengl compositor
>>>
>>> Thanks. What do you mean with "opengl compositor"? Isn't the Gnome3
>>> desktop providing this?
>>
>> Well, it needs to do vsync'ed updates, and to work correctly, the client
>
> Is this in the dri config file?

I've had tear-free video (finally!) in GNOME 3 for a while now, using 
the following in my ~/.xsession (and launching that from GDM instead of 
GNOME directly):

CLUTTER_PAINT=disable-clipped-redraws:disable-culling 
/etc/X11/Sessions/Gnome

You may have to adjust the "/etc/X11/Sessions/Gnome" depending on your 
distribution (I'm on Gentoo).

Hope that helps,

Chun-Yu

Re: Tearing video on Sandy Bridge

[tino.keitel+xorg]

On Thu, May 03, 2012 at 16:32:47 -0400, Chun-Yu Shei wrote:
> On 05/03/2012 03:51 PM, tino.keitel+xorg@tikei.de wrote:
> >On Thu, May 03, 2012 at 21:46:37 +0200, Daniel Vetter wrote:
> >>On Thu, May 03, 2012 at 09:34:28PM +0200, Tino Keitel wrote:
> >>>On Thu, May 03, 2012 at 20:43:01 +0200, Daniel Vetter wrote:
> >>>
> >>>[...]
> >>>
> >>>>The only way to get tear-free screen updates on snb is with pageflips,
> >>>>which requires a opengl compositor
> >>>
> >>>Thanks. What do you mean with "opengl compositor"? Isn't the Gnome3
> >>>desktop providing this?
> >>
> >>Well, it needs to do vsync'ed updates, and to work correctly, the client
> >
> >Is this in the dri config file?
> 
> I've had tear-free video (finally!) in GNOME 3 for a while now,
> using the following in my ~/.xsession (and launching that from GDM
> instead of GNOME directly):
> 
> CLUTTER_PAINT=disable-clipped-redraws:disable-culling
> /etc/X11/Sessions/Gnome

Thanks, I'll try that. When I goggled for that, I also found people
using CLUTTER_VBLANK=True.

Regards,
Tino

Re: Tearing video on Sandy Bridge

[Tino Keitel]

On Fri, May 04, 2012 at 07:56:08 +0200, tino.keitel+xorg@tikei.de wrote:
> On Thu, May 03, 2012 at 16:32:47 -0400, Chun-Yu Shei wrote:
> > On 05/03/2012 03:51 PM, tino.keitel+xorg@tikei.de wrote:
> > >On Thu, May 03, 2012 at 21:46:37 +0200, Daniel Vetter wrote:
> > >>On Thu, May 03, 2012 at 09:34:28PM +0200, Tino Keitel wrote:
> > >>>On Thu, May 03, 2012 at 20:43:01 +0200, Daniel Vetter wrote:
> > >>>
> > >>>[...]
> > >>>
> > >>>>The only way to get tear-free screen updates on snb is with pageflips,
> > >>>>which requires a opengl compositor
> > >>>
> > >>>Thanks. What do you mean with "opengl compositor"? Isn't the Gnome3
> > >>>desktop providing this?
> > >>
> > >>Well, it needs to do vsync'ed updates, and to work correctly, the client
> > >
> > >Is this in the dri config file?
> > 
> > I've had tear-free video (finally!) in GNOME 3 for a while now,
> > using the following in my ~/.xsession (and launching that from GDM
> > instead of GNOME directly):
> > 
> > CLUTTER_PAINT=disable-clipped-redraws:disable-culling
> > /etc/X11/Sessions/Gnome
> 
> Thanks, I'll try that. When I goggled for that, I also found people
> using CLUTTER_VBLANK=True.

Thanks a lot, the CLUTTER_PAINT setting did the trick. The
CLUTTER_VBLANK line had no effect.

Regards,
Tino