Re: [PATCH 13/13 v2] drm/i915/skl: Prefer even dividers for SKL DPLLs

Daniel Vetter
2015-06-26T17:37:01Z

On Fri, Jun 26, 2015 at 02:08:30PM -0300, Paulo Zanoni wrote:
> 2015-06-25 12:19 GMT-03:00 Damien Lespiau <damien.lespiau@intel.com>:
> > Currently, if an odd divider improves the deviation (minimizes it), we
> > take that divider. The recommendation is to prefer even dividers.
> >
> > v2: Move the check at the right place after having inverted the two for
> > loops in the previous patch.
> >
> > Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
>
> Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

Last two patches merged, thanks.
-Daniel

>
> > ---
> > drivers/gpu/drm/i915/intel_ddi.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> > index 6e964ef..f6b3ccc 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -1317,6 +1317,13 @@ skl_ddi_calculate_wrpll(int clock /* in Hz */,
> > p);
> > }
> > }
> > +
> > + /*
> > + * If a solution is found with an even divider, prefer
> > + * this one.
> > + */
> > + if (d == 0 && ctx.p)
> > + break;
> > }
> >
> > if (!ctx.p) {
> > --
> > 2.1.0
> >
>
>
>
> --
> Paulo Zanoni
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--
Daniel Vetter
Software Engineer, Intel Corporation