On Tue, Nov 14, 2017 at 11:47:58AM -0800, Rodrigo Vivi wrote: > I confess I never fully understood that previous calculation, > so maybe this is cannot be called a "fix". But let's follow > the math that is written on Spec so we have get more confident > this is what hardware expect. > > Cc: Mika Kahola <mika.kah...@intel.com> > Cc: Manasi Navare <manasi.d.nav...@intel.com> > Cc: James Ausmus <james.aus...@intel.com> > Signed-off-by: Rodrigo Vivi <rodrigo.v...@intel.com> > --- > drivers/gpu/drm/i915/intel_dpll_mgr.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.c > b/drivers/gpu/drm/i915/intel_dpll_mgr.c > index bd608f7f2399..ee690d2f6e54 100644 > --- a/drivers/gpu/drm/i915/intel_dpll_mgr.c > +++ b/drivers/gpu/drm/i915/intel_dpll_mgr.c > @@ -2190,8 +2190,8 @@ static void cnl_wrpll_params_populate(struct > skl_wrpll_params *params, > params->qdiv_mode = (qdiv == 1) ? 0 : 1; > > params->dco_integer = div_u64(dco_freq, ref_freq); > - params->dco_fraction = div_u64((div_u64((uint64_t)dco_freq<<15, > (uint64_t)ref_freq) - > - ((uint64_t)params->dco_integer<<15)) * > 0x8000, 0x8000); > + params->dco_fraction = (DIV_ROUND_UP_ULL(dco_freq, ref_freq) - > + params->dco_integer) * (1 << 15);
Is dco_freq in khz here? Or hz? If khz, the following should work... I think: unsigned int dco = div_u64((u64)dco_freq << 15, ref_freq * 1000); dco_int = dco >> 15; dco_frac = dco & 0x7fff; > } > > static bool > -- > 2.13.6 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
