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drm/i915/chv: use vlv_PLL_is_optimal in chv_find_best_dpll

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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: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Imre Deak 2015-03-17 11:40:05 +02:00 committed by Daniel Vetter
parent 24be4e4650
commit 9ca3ba011b
1 changed files with 20 additions and 6 deletions
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26
drivers/gpu/drm/i915/intel_display.c
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@ -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;
@ -898,12 +911,13 @@ 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) {
*best_clock = clock;
found = true;
}
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;
}
}