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

Mario Kleiner mario.kleiner.de at gmail.com
Sat Oct 12 01:22:40 CEST 2013


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.
-mario

> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
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