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

[Paulo Zanoni]

2015-06-25 12:19 GMT-03:00 Damien Lespiau <damien.lespiau at 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 at intel.com>

Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

> ---
>  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