Re: drm: Branch 'vblank-rework' - 2 commits

[Jesse B. <jes...@in...>]

On Monday, June 25, 2007 12:44:16 Jesse Barnes wrote:
> On Monday, June 25, 2007 11:46:59 Michel D=C3=A4nzer wrote:
> > On Mon, 2007-06-25 at 08:43 -0700, Jesse Barnes wrote:
> > > On Monday, June 25, 2007 4:00:01 am Michel D=C3=A4nzer wrote:
> > > > On Fri, 2007-06-22 at 11:13 -0700, Jesse Barnes wrote:
> > > > > diff-tree 97dcd7fd25c18d5148619254229f8d94efb55b44 (from
> > > > > 2d24455ed8b12df6d06d135cb70f02473d11f4b0) Author: Jesse
> > > > > Barnes <jes...@in...>
> > > > > Date:   Fri Jun 22 11:06:51 2007 -0700
> > > > >
> > > > >     more vblank rework
> > > > >       - use a timer for disabling vblank events to avoid
> > > > > enable/disable calls too often
> > > > >       - make i915 work with pre-965 chips again (would like
> > > > > to structure this better, but this hack works on my test
> > > > > system)
> > > >
> > > > Can you elaborate on the latter? The previous code seemed to
> > > > work fine on my i915 system...
> > >
> > > Any app wanting to sync to vblank on 915 hung prior to these
> > > mods, since the vblank counter never incremented.  Did you see
> > > that working [...]
> >
> > Yes, I consider sync-to-vblank the main feature for vblank-rework.
> > :)
> >
> > How exactly did you test (vblank_mode=3D2 glxgears here), and did the
> > app(s) hang indefinitely or just initially for three seconds?
>
> IIRC my test app hung indefinitely.  Main loop was something like:
>
>         while (i++) {
>                 /* Wait for vsync */
>                 if (waitforsync)
>                         video_sync(2, (count + 1) % 2, &count);
>
>                 /* Alternate colors to make tearing obvious */
>                 if (i & 1)
>                         glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
>                 else
>                         glClearColor(1.0f, 0.0f, 0.0f, 0.0f);
>                 glClear(GL_COLOR_BUFFER_BIT);
>                 glFlush();
>         }
>
> If waitforsync =3D=3D 0, I get obvious tearing (a kind of "rain" effect
> of the two colors I painted), while if waitforsync !=3D 0, the app
> either hangs
         ^^^^^

P.S.  but I may not have been patient enough to wait for the 3 second=20
timeout... Like I said I'll retest.