On Tue, Nov 14, 2017 at 10:22:27PM +0200, Ville Syrjälä wrote: > 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.kahola@xxxxxxxxx> > > Cc: Manasi Navare <manasi.d.navare@xxxxxxxxx> > > Cc: James Ausmus <james.ausmus@xxxxxxxxx> > > Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> > > --- > > 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); Actually w/o the *1000 I suppose, for khz. > dco_int = dco >> 15; > dco_frac = dco & 0x7fff; > > > } > > > > static bool > > -- > > 2.13.6 > > > > _______________________________________________ > > Intel-gfx mailing list > > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx > > -- > Ville Syrjälä > Intel OTC > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
