Re: [PATCH 31/67] drm/i915/cnl: Allow dynamic cdclk changes on CNL

["Pandiyan, Dhinakaran" <dhinakaran.pandiyan@intel.com>]

On Tue, 2017-06-06 at 11:12 -0700, Rodrigo Vivi wrote:
> On Tue, Jun 6, 2017 at 11:09 AM, Rodrigo Vivi <rodrigo.vivi@gmail.com> wrote:
> > On Tue, Jun 6, 2017 at 10:39 AM, Pandiyan, Dhinakaran
> > <dhinakaran.pandiyan@intel.com> wrote:
> >> On Tue, 2017-06-06 at 08:24 -0700, Rodrigo Vivi wrote:
> >>> On Mon, Jun 5, 2017 at 10:04 AM, Pandiyan, Dhinakaran
> >>> <dhinakaran.pandiyan@intel.com> wrote:
> >>> > On Mon, 2017-06-05 at 19:55 +0300, Ville Syrjälä wrote:
> >>> >> On Mon, Jun 05, 2017 at 04:41:07PM +0000, Vivi, Rodrigo wrote:
> >>> >> > On Mon, 2017-06-05 at 18:22 +0300, Imre Deak wrote:
> >>> >> > > On Thu, Apr 06, 2017 at 12:15:27PM -0700, Rodrigo Vivi wrote:
> >>> >> > > > All the low level cdclk bits are present, so let's add the required
> >>> >> > > > hooks to reconfigure cdclk on the fly.
> >>> >> > > >
> >>> >> > > > v2: Rebase due to cnl_sanitize_cdclk()
> >>> >> > > > v3: Rebased by Rodrigo on top of Ville's cdclk rework.
> >>> >> > > > v4: Rebase moving cnl_calc_cdclk up to follow same order
> >>> >> > > >     as previous platforms.
> >>> >> > > >
> >>> >> > > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >>> >> > > > Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> >>> >> > > > ---
> >>> >> > > >  drivers/gpu/drm/i915/intel_cdclk.c | 54 ++++++++++++++++++++++++++++++++++++--
> >>> >> > > >  1 file changed, 52 insertions(+), 2 deletions(-)
> >>> >> > > >
> >>> >> > > > diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c
> >>> >> > > > index f9ba1e7..a8c254b 100644
> >>> >> > > > --- a/drivers/gpu/drm/i915/intel_cdclk.c
> >>> >> > > > +++ b/drivers/gpu/drm/i915/intel_cdclk.c
> >>> >> > > > @@ -1400,6 +1400,16 @@ void bxt_uninit_cdclk(struct drm_i915_private *dev_priv)
> >>> >> > > >         bxt_set_cdclk(dev_priv, &cdclk_state);
> >>> >> > > >  }
> >>> >> > > >
> >>> >> > > > +static int cnl_calc_cdclk(int max_pixclk)
> >>> >> > > > +{
> >>> >> > > > +       if (max_pixclk > 336000)
> >>> >> > > > +               return 528000;
> >>> >> > > > +       else if (max_pixclk > 168000)
> >>> >> > > > +               return 336000;
> >>> >> > > > +       else
> >>> >> > > > +               return 168000;
> >>> >> > > > +}
> >>> >> > > > +
> >>> >> > > >  static void cnl_cdclk_pll_update(struct drm_i915_private *dev_priv,
> >>> >> > > >                                  struct intel_cdclk_state *cdclk_state)
> >>> >> > > >  {
> >>> >> > > > @@ -1640,7 +1650,7 @@ void cnl_init_cdclk(struct drm_i915_private *dev_priv)
> >>> >> > > >
> >>> >> > > >         cdclk_state = dev_priv->cdclk.hw;
> >>> >> > > >
> >>> >> > > > -       cdclk_state.cdclk = 168000;
> >>> >> > > > +       cdclk_state.cdclk = cnl_calc_cdclk(0);
> >>> >> > > >         cdclk_state.vco = cnl_cdclk_pll_vco(dev_priv, cdclk_state.cdclk);
> >>> >> > > >
> >>> >> > > >         cnl_set_cdclk(dev_priv, &cdclk_state);
> >>> >> > > > @@ -1928,6 +1938,40 @@ static int bxt_modeset_calc_cdclk(struct drm_atomic_state *state)
> >>> >> > > >         return 0;
> >>> >> > > >  }
> >>> >> > > >
> >>> >> > > > +static int cnl_modeset_calc_cdclk(struct drm_atomic_state *state)
> >>> >> > > > +{
> >>> >> > > > +       struct drm_i915_private *dev_priv = to_i915(state->dev);
> >>> >> > > > +       struct intel_atomic_state *intel_state =
> >>> >> > > > +               to_intel_atomic_state(state);
> >>> >> > > > +       int max_pixclk = intel_max_pixel_rate(state);
> >>> >> > > > +       int cdclk, vco;
> >>> >> > > > +
> >>> >> > > > +       cdclk = cnl_calc_cdclk(max_pixclk);
> >>> >> > > > +       vco = cnl_cdclk_pll_vco(dev_priv, cdclk);
> >>> >> > >
> >>> >> > > The spec says not to set CDCLK to 168MHz if audio is used with 96MHz
> >>> >> > > BCLK, what's the plan to add that constraint? At least there could be a
> >>> >> > > TODO: here.
> >>> >> >
> >>> >> > That's a good question.
> >>> >> > Do we have ways to know the audio freq?
> >>> >> > Or we need to add few extra hooks?
> >>> >> > And agree, at least a TODO or FIXME here is needed while we dont have a
> >>> >> > clear path.
> >>> >>
> >>> >> bdw_adjust_min_pipe_pixel_rate() just assumes 96MHz. There was some
> >>> >> discussion on the topic, and I found some register that possibly could
> >>> >> tell us something. But the best solution would probably involve querying
> >>> >> it from the audio driver.
> >>> >>
> >>> >
> >>> > The last time I checked with the audio folks, the driver does not change
> >>> > the BCLK freq. and the default is 96 MHz.
> >>>
> >>> So, what should we do for now? Block 168? Remove 168?
> >>
> >> As Ville wrote, bdw_adjust_min_pipe_pixel_rate() already does that. You
> >> just have to modify intel_max_pixel_rate() to include CNL too.
> >
> 
> oh, so just squash [PATCH 67/67] drm/i915/cnl: Adjust min pixelrate.
> here?
> 

I completely forgot about that patch, makes sense to squash that here.



> >
> >>
> >> -DK
> >>
> >>>
> >>> >
> >>> >
> >>> >> >
> >>> >> > >
> >>> >> > > > +
> >>> >> > > > +       if (cdclk > dev_priv->max_cdclk_freq) {
> >>> >> > > > +               DRM_DEBUG_KMS("requested cdclk (%d kHz) exceeds max (%d kHz)\n",
> >>> >> > > > +                             cdclk, dev_priv->max_cdclk_freq);
> >>> >> > > > +               return -EINVAL;
> >>> >> > > > +       }
> >>> >> > > > +
> >>> >> > > > +       intel_state->cdclk.logical.vco = vco;
> >>> >> > > > +       intel_state->cdclk.logical.cdclk = cdclk;
> >>> >> > > > +
> >>> >> > > > +       if (!intel_state->active_crtcs) {
> >>> >> > > > +               cdclk = cnl_calc_cdclk(0);
> >>> >> > > > +               vco = cnl_cdclk_pll_vco(dev_priv, cdclk);
> >>> >> > > > +
> >>> >> > > > +               intel_state->cdclk.actual.vco = vco;
> >>> >> > > > +               intel_state->cdclk.actual.cdclk = cdclk;
> >>> >> > > > +       } else {
> >>> >> > > > +               intel_state->cdclk.actual =
> >>> >> > > > +                       intel_state->cdclk.logical;
> >>> >> > > > +       }
> >>> >> > > > +
> >>> >> > > > +       return 0;
> >>> >> > > > +}
> >>> >> > > > +
> >>> >> > > >  static int intel_compute_max_dotclk(struct drm_i915_private *dev_priv)
> >>> >> > > >  {
> >>> >> > > >         int max_cdclk_freq = dev_priv->max_cdclk_freq;
> >>> >> > > > @@ -1959,7 +2003,9 @@ static int intel_compute_max_dotclk(struct drm_i915_private *dev_priv)
> >>> >> > > >   */
> >>> >> > > >  void intel_update_max_cdclk(struct drm_i915_private *dev_priv)
> >>> >> > > >  {
> >>> >> > > > -       if (IS_GEN9_BC(dev_priv)) {
> >>> >> > > > +       if (IS_CANNONLAKE(dev_priv)) {
> >>> >> > > > +               dev_priv->max_cdclk_freq = 528000;
> >>> >> > > > +       } else if (IS_GEN9_BC(dev_priv)) {
> >>> >> > > >                 u32 limit = I915_READ(SKL_DFSM) & SKL_DFSM_CDCLK_LIMIT_MASK;
> >>> >> > > >                 int max_cdclk, vco;
> >>> >> > > >
> >>> >> > > > @@ -2158,6 +2204,10 @@ void intel_init_cdclk_hooks(struct drm_i915_private *dev_priv)
> >>> >> > > >                 dev_priv->display.set_cdclk = skl_set_cdclk;
> >>> >> > > >                 dev_priv->display.modeset_calc_cdclk =
> >>> >> > > >                         skl_modeset_calc_cdclk;
> >>> >> > > > +       } else if (IS_CANNONLAKE(dev_priv)) {
> >>> >> > > > +               dev_priv->display.set_cdclk = cnl_set_cdclk;
> >>> >> > > > +               dev_priv->display.modeset_calc_cdclk =
> >>> >> > > > +                       cnl_modeset_calc_cdclk;
> >>> >> > > >         }
> >>> >> > > >
> >>> >> > > >         if (IS_CANNONLAKE(dev_priv))
> >>> >> > > > --
> >>> >> > > > 1.9.1
> >>> >> > > >
> >>> >> > > > _______________________________________________
> >>> >> > > > Intel-gfx mailing list
> >>> >> > > > Intel-gfx@lists.freedesktop.org
> >>> >> > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >>> >> >
> >>> >>
> >>> >
> >>> > _______________________________________________
> >>> > Intel-gfx mailing list
> >>> > Intel-gfx@lists.freedesktop.org
> >>> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >>>
> >>>
> >>>
> >>
> >
> >
> >
> > --
> > Rodrigo Vivi
> > Blog: http://blog.vivi.eng.br
> 
> 
> 

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