[Bug 42035] no way to turn off vsync

[Michel Dänzer]

On Die, 2011-10-25 at 20:41 +0200, Michal Suchanek wrote: 
> 2011/10/25 Michel Dänzer <michel at daenzer.net>:
> > On Mon, 2011-10-24 at 23:23 +0200, Michal Suchanek wrote:
> >> With this patch it should be at least possible to turn off all this
> >> when it does not work.
> >
> > Exactly. So, have you had a chance to try it?
> 
> I installed the packages I built yesterday. The patch has no visible effect.

Well, I do see an effect in the log file:

[2558366.995] (==) RADEON(0): SwapBuffers wait for vblank: disabled


> > Does it address your bug report?
> 
> I am not quite sure.

The above means the thing the bug report complains about being
impossible to disable is disabled.

> With the current Radeon driver ( xserver-xorg-video-radeon
> 1:6.14.99+git20111024.856583db-0ubuntu0sarvatt~natty patched or not)
> and X server 1.10.4 I could reliably reproduce a lockup on start of
> glxgears on the primary screen with vsync enabled in drirc.

That would be a different bug then. You could try finding out where
things get stuck by attaching gdb to glxgears and/or the X server.

> With vsync disabled in drirc and at any time on the secondary screen
> glxgears would run uncapped.
> 
> This is different from what my running X server (with some older
> radeon driver) exhibits currently but as it varies with time I am not
> sure if that's of any consequence.

Sounds like yet another problem with the vline wait code.


-- 
Earthling Michel Dänzer           |                   http://www.amd.com
Libre software enthusiast         |          Debian, X and DRI developer