On Tue, 2023-05-23 at 16:14 +0300, Jani Nikula wrote: > On Tue, 23 May 2023, "Govindapillai, Vinod" <vinod.govindapillai@xxxxxxxxx> wrote: > > On Tue, 2023-05-23 at 12:01 +0300, Jani Nikula wrote: > > > On Tue, 23 May 2023, Vinod Govindapillai <vinod.govindapillai@xxxxxxxxx> wrote: > > > > From MTL onwwards, pcode locks the QGV point based on peak BW of > > > > the intended QGV point passed by the driver. So the peak BW > > > > calculation must match the value expected by the pcode. Update > > > > the calculations as per the Bspec. > > > > > > > > v2: use DIV_ROUND_* macro for the calculations (Ville) > > > > > > > > Bspec: 64636 > > > > > > > > Signed-off-by: Vinod Govindapillai <vinod.govindapillai@xxxxxxxxx> > > > > Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx> > > > > --- > > > > drivers/gpu/drm/i915/display/intel_bw.c | 2 +- > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_bw.c > > > > b/drivers/gpu/drm/i915/display/intel_bw.c > > > > index ab405c48ca3a..c8075a37c3ab 100644 > > > > --- a/drivers/gpu/drm/i915/display/intel_bw.c > > > > +++ b/drivers/gpu/drm/i915/display/intel_bw.c > > > > @@ -182,7 +182,7 @@ static int mtl_read_qgv_point_info(struct drm_i915_private *dev_priv, > > > > val2 = intel_uncore_read(&dev_priv->uncore, > > > > MTL_MEM_SS_INFO_QGV_POINT_HIGH(point)); > > > > dclk = REG_FIELD_GET(MTL_DCLK_MASK, val); > > > > - sp->dclk = DIV_ROUND_UP((16667 * dclk), 1000); > > > > + sp->dclk = DIV_ROUND_CLOSEST(16667 * dclk + 500, 1000); > > > > > > What's with the +500 there? > > > > This is what pcode expects. Somehow pcode use this formula and we have to exactly match this. > > Got > > this confirmed from Art. > > I'm guessing all it really means is to round to closest, and they > specified it like that instead of saying "round to closest". > > Essentially (x + (div/2)) / div is what DIV_ROUND_CLOSEST() does. > > It's odd to do it *twice*, and surely not what they expect. > > BR, > Jani. Ah.. ok! Thanks! will update this! BR Vinod > > > > > BR > > Vinod > > > > > > > > BR, > > > Jani. > > > > > > > > > > sp->t_rp = REG_FIELD_GET(MTL_TRP_MASK, val); > > > > sp->t_rcd = REG_FIELD_GET(MTL_TRCD_MASK, val); > > > > > >
