On 03/17/2015 02:40 AM, Imre Deak wrote: > 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 <[email protected]> > --- > drivers/gpu/drm/i915/intel_display.c | 26 ++++++++++++++++++++------ > 1 file changed, 20 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_display.c > b/drivers/gpu/drm/i915/intel_display.c > index 5874512..9ca84a2 100644 > --- a/drivers/gpu/drm/i915/intel_display.c > +++ b/drivers/gpu/drm/i915/intel_display.c > @@ -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; > } > } > >
Looking at it again, maybe vlv_PLL_is_better() might be a better name. Also, could you just make the ppm variable a scratch one and ignore it? It just gets set to 0 no matter what, right? Reviewed-by: Jesse Barnes <[email protected]> _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
