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

Paulo Zanoni
2015-06-26T17:08:30Z

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>

> ---
> 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