[Intel-gfx] [PATCH v2] drm/i915/display: Set correct voltage level for 480MHz CDCLK

[Matt Roper]

On Wed, May 31, 2023 at 11:08:12AM +0000, Kahola, Mika wrote:
> > -----Original Message-----
> > From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Chaitanya Kumar Borah
> > Sent: Monday, May 29, 2023 9:08 AM
> > To: intel-gfx at lists.freedesktop.org
> > Cc: Roper, Matthew D <matthew.d.roper at intel.com>
> > Subject: [Intel-gfx] [PATCH v2] drm/i915/display: Set correct voltage level for 480MHz CDCLK
> > 
> > According to Bspec, the voltage level for 480MHz is to be set as 1 instead of 2.
> > 
> > BSpec: 49208
> > 
> > Fixes: 06f1b06dc5b7 ("drm/i915/display: Add 480 MHz CDCLK steps for RPL-U")
> > 
> > v2: rebase
> > 
> > Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_cdclk.c | 30 +++++++++++++++++++---
> >  1 file changed, 26 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
> > index 6bed75f1541a..1a5268e3d0a3 100644
> > --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> > @@ -1453,6 +1453,18 @@ static u8 tgl_calc_voltage_level(int cdclk)
> >  		return 0;
> >  }
> > 
> > +static u8 rplu_calc_voltage_level(int cdclk) {
> > +	if (cdclk > 556800)
> > +		return 3;
> > +	else if (cdclk > 480000)
> > +		return 2;
> > +	else if (cdclk > 312000)
> > +		return 1;
> > +	else
> > +		return 0;
> > +}
> 
> The spec defines that we should use level 1 in case of SKU supports 480MHz cd clock and max DDI symbol clock is less than or equal to 594MHz. I didn't spot from the spec a scenario where we would have SKU with 480 MHz cd clock frequency and the DDI symbol clock rate would exceed 594MHz.
> 
> Therefore, the change looks ok to me.
> 
> Reviewed-by: Mika Kahola <mika.kahola at intel.com>

Applied to drm-intel-next.  Thanks for the patch and review.


Matt

> 
> > +
> >  static void icl_readout_refclk(struct drm_i915_private *dev_priv,
> >  			       struct intel_cdclk_config *cdclk_config)  { @@ -3397,6 +3409,13 @@ static const struct
> > intel_cdclk_funcs mtl_cdclk_funcs = {
> >  	.calc_voltage_level = tgl_calc_voltage_level,  };
> > 
> > +static const struct intel_cdclk_funcs rplu_cdclk_funcs = {
> > +	.get_cdclk = bxt_get_cdclk,
> > +	.set_cdclk = bxt_set_cdclk,
> > +	.modeset_calc_cdclk = bxt_modeset_calc_cdclk,
> > +	.calc_voltage_level = rplu_calc_voltage_level, };
> > +
> >  static const struct intel_cdclk_funcs tgl_cdclk_funcs = {
> >  	.get_cdclk = bxt_get_cdclk,
> >  	.set_cdclk = bxt_set_cdclk,
> > @@ -3539,14 +3558,17 @@ void intel_init_cdclk_hooks(struct drm_i915_private *dev_priv)
> >  		dev_priv->display.funcs.cdclk = &tgl_cdclk_funcs;
> >  		dev_priv->display.cdclk.table = dg2_cdclk_table;
> >  	} else if (IS_ALDERLAKE_P(dev_priv)) {
> > -		dev_priv->display.funcs.cdclk = &tgl_cdclk_funcs;
> >  		/* Wa_22011320316:adl-p[a0] */
> > -		if (IS_ADLP_DISPLAY_STEP(dev_priv, STEP_A0, STEP_B0))
> > +		if (IS_ADLP_DISPLAY_STEP(dev_priv, STEP_A0, STEP_B0)) {
> >  			dev_priv->display.cdclk.table = adlp_a_step_cdclk_table;
> > -		else if (IS_ADLP_RPLU(dev_priv))
> > +			dev_priv->display.funcs.cdclk = &tgl_cdclk_funcs;
> > +		} else if (IS_ADLP_RPLU(dev_priv)) {
> >  			dev_priv->display.cdclk.table = rplu_cdclk_table;
> > -		else
> > +			dev_priv->display.funcs.cdclk = &rplu_cdclk_funcs;
> > +		} else {
> >  			dev_priv->display.cdclk.table = adlp_cdclk_table;
> > +			dev_priv->display.funcs.cdclk = &tgl_cdclk_funcs;
> > +		}
> >  	} else if (IS_ROCKETLAKE(dev_priv)) {
> >  		dev_priv->display.funcs.cdclk = &tgl_cdclk_funcs;
> >  		dev_priv->display.cdclk.table = rkl_cdclk_table;
> > --
> > 2.25.1
> 

-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation