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Commit 9ca3ba01 authored by Imre Deak's avatar Imre Deak Committed by Daniel Vetter
Browse files

drm/i915/chv: use vlv_PLL_is_optimal in chv_find_best_dpll 



Prepare chv_find_best_dpll to be used for BXT too, where we want to
consider the error between target and calculated frequency too when
choosing a better PLL configuration.

No functional change.

Signed-off-by: default avatarImre Deak <imre.deak@intel.com>
Reviewed-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 24be4e46

drivers/gpu/drm/i915/intel_display.c

+20 −6
Original line number Diff line number Diff line
@@ -786,6 +786,16 @@ static bool vlv_PLL_is_optimal(struct drm_device *dev, int target_freq, 
			       unsigned int best_error_ppm,

			       unsigned int *error_ppm)

{

	/*

	 * For CHV ignore the error and consider only the P value.

	 * Prefer a bigger P value based on HW requirements.

	 */

	if (IS_CHERRYVIEW(dev)) {

		*error_ppm = 0;



		return calculated_clock->p > best_clock->p;

	}



	if (WARN_ON_ONCE(!target_freq))

		return false;
@@ -864,11 +874,13 @@ chv_find_best_dpll(const intel_limit_t *limit, struct intel_crtc *crtc, 
		   intel_clock_t *best_clock)

{

	struct drm_device *dev = crtc->base.dev;

	unsigned int best_error_ppm;

	intel_clock_t clock;

	uint64_t m2;

	int found = false;



	memset(best_clock, 0, sizeof(*best_clock));

	best_error_ppm = 1000000;



	/*

	 * Based on hardware doc, the n always set to 1, and m1 always
@@ -882,6 +894,7 @@ chv_find_best_dpll(const intel_limit_t *limit, struct intel_crtc *crtc, 
		for (clock.p2 = limit->p2.p2_fast;

				clock.p2 >= limit->p2.p2_slow;

				clock.p2 -= clock.p2 > 10 ? 2 : 1) {

			unsigned int error_ppm;



			clock.p = clock.p1 * clock.p2;
@@ -898,14 +911,15 @@ chv_find_best_dpll(const intel_limit_t *limit, struct intel_crtc *crtc, 
			if (!intel_PLL_is_valid(dev, limit, &clock))

				continue;



			/* based on hardware requirement, prefer bigger p

			 */

			if (clock.p > best_clock->p) {

			if (!vlv_PLL_is_optimal(dev, target, &clock, best_clock,

						best_error_ppm, &error_ppm))

				continue;



			*best_clock = clock;

			best_error_ppm = error_ppm;

			found = true;

		}

	}

	}



	return found;

}