[Intel-gfx] [PATCH] drm/i915: fix WRPLL clock calculation

[Paulo Zanoni]

2014/1/22 Jesse Barnes <jbarnes at virtuousgeek.org>:
> Forgot to convert to using the refclk variable when I added refclk
> readout support, and Paulo noticed the resulting calculation was off due
> to the way p & r are stored.
>
> Reported-by: Paulo Zanoni <przanoni at gmail.com>
> Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>

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

> ---
>  drivers/gpu/drm/i915/intel_ddi.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index fe2967e..cd65dd0 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -663,7 +663,8 @@ static int intel_ddi_calc_wrpll_link(struct drm_i915_private *dev_priv,
>         p = (wrpll & WRPLL_DIVIDER_POST_MASK) >> WRPLL_DIVIDER_POST_SHIFT;
>         n = (wrpll & WRPLL_DIVIDER_FB_MASK) >> WRPLL_DIVIDER_FB_SHIFT;
>
> -       return (LC_FREQ * n) / (p * r);
> +       /* Convert to KHz, p & r have a fixed point portion */
> +       return (refclk * n * 100) / (p * r);
>  }
>
>  static void intel_ddi_clock_get(struct intel_encoder *encoder,
> --
> 1.8.3.2
>
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-- 
Paulo Zanoni