[Intel-gfx] [PATCH 2/3] drm/i915: Fix scanoutpos calculations

[Daniel Vetter]

On Sat, Oct 12, 2013 at 01:22:40AM +0200, Mario Kleiner wrote:
> Yes.
> On Oct 12, 2013 1:18 AM, "Daniel Vetter" <daniel at ffwll.ch> wrote:
> >
> > On Fri, Oct 11, 2013 at 04:31:38PM +0200, Mario Kleiner wrote:
> > > Daniel, Ville,
> > >
> > > i tested Ville's patch series for the scanoutpos improvements on a
> > > GMA-950, on top of airlied's current drm-next branch.
> > >
> > > There's one issue: The variable "position" in
> > > i915_get_crtc_scanoutpos() must be turned from a u32 into a int,
> > > otherwise funny sign errors happen and we end up with *vpos being
> > > off by multiple million scanlines and timestamps being off by over
> > > 60 seconds.
> > >
> > > Other than that looks good. Execution time is now better:
> > >
> > > Before uncore.lock addition: 3-4 usecs execution time for the
> > > scanoutpos query on my machine. After uncore.lock addition
> > > (3.12.0-rc3) 9-20 usecs, sometimes repetition of the timing loop
> > > triggered. After Ville's patches down to typically 3-8 usecs,
> > > occassionally spiking to almost 20 usecs.
> > >
> > > I'll make my patches for the realtime kernel + increased accuracy on
> > > top of drm-next + Ville's patches.
> >
> > So official reviewed-by/tested-by from you on Ville's latest patches in
> > this thread?
> 
> Yes.

Ok, slurped in the entire series, thanks for the review and testing.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch