Re: [PATCH 7/8] drm/i915: Use cdclk_state->voltage on CNL

Rodrigo Vivi
2017-10-18T22:43:19Z

On Wed, Oct 18, 2017 at 09:50:59PM +0000, Rodrigo Vivi wrote:
> On Wed, Oct 18, 2017 at 08:48:24PM +0000, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > Track the system agent voltage we request from pcode in the cdclk state
> > on CNL. Annoyingly we can't actually read out the current value since
> > there's no pcode command to do that, so we'll have to just assume that
> > it worked.
>
> +static u32 cnl_cur_voltage(struct drm_i915_private *dev_priv)
> +{
> + u32 voltage;
> + sandybridge_pcode_read(dev_priv, SKL_PCODE_CDCLK_CONTROL, &voltage);
> + return voltage;
> +}
> +
> static void cnl_get_cdclk(struct drm_i915_private *dev_priv,
> struct intel_cdclk_state *cdclk_state)
> {
> @@ -1486,8 +1493,7 @@ static void cnl_get_cdclk(struct drm_i915_private *dev_priv,
>
> cdclk_state->cdclk = DIV_ROUND_CLOSEST(cdclk_state->vco, div);
>
> + cdclk_state->voltage = cnl_cur_voltage(dev_priv);
> }
>
> static void cnl_cdclk_pll_disable(struct drm_i915_private *dev_priv)
> @@ -1594,8 +1600,7 @@ static void cnl_set_cdclk(struct drm_i915_private *dev_priv,
>
> intel_update_cdclk(dev_priv);
>
> + dev_priv->cdclk.hw.voltage = cnl_cur_voltage(dev_priv);

Hmm... read works, but it triggers a
[ 337.907234] [drm:pipe_config_err [i915]] *ERROR* mismatch in min_voltage (expected 0, found 1)

Because the hw voltage is global while the minimal local is only relative to that pipe.

I'm playing here with changes on top of the branch you sent yesterday...

git://people.freedesktop.org/~vivijim/drm-intel dvfs-atomic

trying to add the port_clock to the picture and the hw_state readout..

main doubt is where to get port_clock from during
cnl_modeset_calc_cdclk?

>
>
> >
> > Cc: Mika Kahola <mika.kahola@intel.com>
> > Cc: Manasi Navare <manasi.d.navare@intel.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> > drivers/gpu/drm/i915/intel_cdclk.c | 44 ++++++++++++++++++++++++--------------
> > 1 file changed, 28 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c
> > index 1b4dcd9689da..795a18f64c4c 100644
> > --- a/drivers/gpu/drm/i915/intel_cdclk.c
> > +++ b/drivers/gpu/drm/i915/intel_cdclk.c
> > @@ -1505,6 +1505,19 @@ static int cnl_calc_cdclk(int min_cdclk)
> > return 168000;
> > }
> >
> > +static u8 cnl_calc_voltage(int cdclk)
> > +{
> > + switch (cdclk) {
> > + default:
> > + case 168000:
> > + return 0;
> > + case 336000:
> > + return 1;
> > + case 528000:
> > + return 2;
> > + }
> > +}
>
> where is the port_clock taking into account?
>
> > +
> > static void cnl_cdclk_pll_update(struct drm_i915_private *dev_priv,
> > struct intel_cdclk_state *cdclk_state)
> > {
> > @@ -1538,7 +1551,7 @@ static void cnl_get_cdclk(struct drm_i915_private *dev_priv,
> > cdclk_state->cdclk = cdclk_state->ref;
> >
> > if (cdclk_state->vco == 0)
> > - return;
> > + goto out;
> >
> > divider = I915_READ(CDCLK_CTL) & BXT_CDCLK_CD2X_DIV_SEL_MASK;
> >
> > @@ -1555,6 +1568,13 @@ static void cnl_get_cdclk(struct drm_i915_private *dev_priv,
> > }
> >
> > cdclk_state->cdclk = DIV_ROUND_CLOSEST(cdclk_state->vco, div);
> > +
> > + out:
> > + /*
> > + * Can't read this out :( Let's assume it's
> > + * at least what the CDCLK frequency requires.
> > + */
> > + cdclk_state->voltage = cnl_calc_voltage(cdclk_state->cdclk);
> > }
> >
> > static void cnl_cdclk_pll_disable(struct drm_i915_private *dev_priv)
> > @@ -1595,7 +1615,7 @@ static void cnl_set_cdclk(struct drm_i915_private *dev_priv,
> > {
> > int cdclk = cdclk_state->cdclk;
> > int vco = cdclk_state->vco;
> > - u32 val, divider, pcu_ack;
> > + u32 val, divider;
> > int ret;
> >
> > mutex_lock(&dev_priv->pcu_lock);
> > @@ -1624,19 +1644,6 @@ static void cnl_set_cdclk(struct drm_i915_private *dev_priv,
> > break;
> > }
> >
> > - switch (cdclk) {
> > - case 528000:
> > - pcu_ack = 2;
> > - break;
> > - case 336000:
> > - pcu_ack = 1;
> > - break;
> > - case 168000:
> > - default:
> > - pcu_ack = 0;
> > - break;
> > - }
> > -
> > if (dev_priv->cdclk.hw.vco != 0 &&
> > dev_priv->cdclk.hw.vco != vco)
> > cnl_cdclk_pll_disable(dev_priv);
> > @@ -1654,7 +1661,8 @@ static void cnl_set_cdclk(struct drm_i915_private *dev_priv,
> >
> > /* inform PCU of the change */
> > mutex_lock(&dev_priv->pcu_lock);
> > - sandybridge_pcode_write(dev_priv, SKL_PCODE_CDCLK_CONTROL, pcu_ack);
> > + sandybridge_pcode_write(dev_priv, SKL_PCODE_CDCLK_CONTROL,
> > + cdclk_state->voltage);
> > mutex_unlock(&dev_priv->pcu_lock);
> >
> > intel_update_cdclk(dev_priv);
> > @@ -1747,6 +1755,7 @@ void cnl_init_cdclk(struct drm_i915_private *dev_priv)
> >
> > cdclk_state.cdclk = cnl_calc_cdclk(0);
> > cdclk_state.vco = cnl_cdclk_pll_vco(dev_priv, cdclk_state.cdclk);
> > + cdclk_state.voltage = cnl_calc_voltage(cdclk_state.cdclk);
> >
> > cnl_set_cdclk(dev_priv, &cdclk_state);
> > }
> > @@ -1764,6 +1773,7 @@ void cnl_uninit_cdclk(struct drm_i915_private *dev_priv)
> >
> > cdclk_state.cdclk = cdclk_state.ref;
> > cdclk_state.vco = 0;
> > + cdclk_state.voltage = cnl_calc_voltage(cdclk_state.cdclk);
> >
> > cnl_set_cdclk(dev_priv, &cdclk_state);
> > }
> > @@ -2081,6 +2091,7 @@ static int cnl_modeset_calc_cdclk(struct drm_atomic_state *state)
> >
> > intel_state->cdclk.logical.vco = vco;
> > intel_state->cdclk.logical.cdclk = cdclk;
> > + intel_state->cdclk.logical.voltage = cnl_calc_voltage(cdclk);
> >
> > if (!intel_state->active_crtcs) {
> > cdclk = cnl_calc_cdclk(0);
> > @@ -2088,6 +2099,7 @@ static int cnl_modeset_calc_cdclk(struct drm_atomic_state *state)
> >
> > intel_state->cdclk.actual.vco = vco;
> > intel_state->cdclk.actual.cdclk = cdclk;
> > + intel_state->cdclk.actual.voltage = cnl_calc_voltage(cdclk);
> > } else {
> > intel_state->cdclk.actual =
> > intel_state->cdclk.logical;
> > --
> > 2.13.6
> >