drm/i915: Use DIV_ROUND_UP() when calculating number of required FDI lanes

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@linux.intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Ville Syrjälä 2014-02-27 14:23:14 +02:00 committed by Daniel Vetter
parent 8f7abfd822
commit 619d4d0472

View file

@ -6161,7 +6161,7 @@ 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)