[Intel-gfx] [PATCH 3/5] drm/i915: Use DIV_ROUND_UP() when calculating number of required FDI lanes

[Paulo Zanoni]

2014-02-27 9:23 GMT-03:00  <ville.syrjala at linux.intel.com>:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> If we need precisely N lanes to satisfy the FDI bandwidth requirement,
> the code would still claim that we need N+1 lanes. Use DIV_ROUND_UP()
> to get a more accurate answer.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

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

> ---
>  drivers/gpu/drm/i915/intel_display.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index a366e91..4702858 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -6149,7 +6149,7 @@ int ironlake_get_lanes_required(int target_clock, int link_bw, int bpp)
>          * is 2.5%; use 5% for safety's sake.
>          */
>         u32 bps = target_clock * bpp * 21 / 20;
> -       return bps / (link_bw * 8) + 1;
> +       return DIV_ROUND_UP(bps, link_bw * 8);
>  }
>
>  static bool ironlake_needs_fb_cb_tune(struct dpll *dpll, int factor)
> --
> 1.8.3.2
>
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-- 
Paulo Zanoni