Re: [PATCH 1/3] drm/i915/icl: Add new supported CD clocks

Souza, Jose
2019-06-20T23:33:29Z

On Wed, 2019-06-19 at 20:47 +0300, Ville Syrjälä wrote:
> On Tue, Jun 18, 2019 at 03:50:33PM -0700, José Roberto de Souza
> wrote:
> > Now 180, 172.8 and 192 MHz are supported.
> >
> > 180 and 172.8 MHz CD clocks will only be used when audio is not
> > enabled as state by BSpec and implemented in
> > intel_crtc_compute_min_cdclk(), CD clock must be at least twice of
> > Azalia BCLK and BCLK by default is 96 MHz, it could be set to 48
> > MHz
> > but we are not reading it.
>
> Do we know whether this thing still suffers from the glk/cnl issue
> where
> we can't even talk to the codec if cdclk is too low? If it does we
> need
> to adjust the platform check for the "force min cdclk for audio"
> thing.
> Also that is going to suck on icl due to the cd2x divider always
> being
> 1 and hence we can't do the optimized cdclk change around audio power
> requests.

Not sure how to test if we can talk to the codec when cdclock is too
low(you mean lower than 192000khz(96MHz*2)?) but this workflow worked:

1- only full HD eDP panel connected | cdclock = 172800khz
2- connected a full HD DP monitor with audio | cdclock = 192000khz
* audio works
3- disconnected full HD DP monitor | cdclock = 172800khz
4- connected again a full HD DP monitor with audio | cdclock =
192000khz
* audio works

Do you have any other test in mind?

>
> > BSpec: 20598
> > BSpec: 15729
> > Cc: Clint Taylor <Clinton.A.Taylor@intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> > ---
> > drivers/gpu/drm/i915/display/intel_cdclk.c | 29 +++++++++++++++---
> > ----
> > 1 file changed, 20 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c
> > b/drivers/gpu/drm/i915/display/intel_cdclk.c
> > index 8993ab283562..d560e25d3fb5 100644
> > --- a/drivers/gpu/drm/i915/display/intel_cdclk.c
> > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
> > @@ -1756,9 +1756,10 @@ static void cnl_sanitize_cdclk(struct
> > drm_i915_private *dev_priv)
> >
> > static int icl_calc_cdclk(int min_cdclk, unsigned int ref)
> > {
> > - int ranges_24[] = { 312000, 552000, 648000 };
> > - int ranges_19_38[] = { 307200, 556800, 652800 };
> > - int *ranges;
> > + const int ranges_24[] = { 180000, 192000, 312000, 552000,
> > 648000 };
> > + const int ranges_19_38[] = { 172800, 192000, 307200, 556800,
> > 652800 };
> > + const int *ranges;
> > + unsigned int len, i;
> >
> > switch (ref) {
> > default:
> > @@ -1766,19 +1767,22 @@ static int icl_calc_cdclk(int min_cdclk,
> > unsigned int ref)
> > /* fall through */
> > case 24000:
> > ranges = ranges_24;
> > + len = ARRAY_SIZE(ranges_24);
> > break;
> > case 19200:
> > case 38400:
> > ranges = ranges_19_38;
> > + len = ARRAY_SIZE(ranges_19_38);
> > break;
> > }
> >
> > - if (min_cdclk > ranges[1])
> > - return ranges[2];
> > - else if (min_cdclk > ranges[0])
> > - return ranges[1];
> > - else
> > - return ranges[0];
> > + for (i = 0; i < len; i++) {
> > + if (min_cdclk <= ranges[i])
> > + return ranges[i];
> > + }
> > +
> > + WARN_ON(min_cdclk > ranges[len - 1]);
> > + return ranges[len - 1];
> > }
> >
> > static int icl_calc_cdclk_pll_vco(struct drm_i915_private
> > *dev_priv, int cdclk)
> > @@ -1792,16 +1796,23 @@ static int icl_calc_cdclk_pll_vco(struct
> > drm_i915_private *dev_priv, int cdclk)
> > default:
> > MISSING_CASE(cdclk);
> > /* fall through */
> > + case 172800:
> > case 307200:
> > case 556800:
> > case 652800:
> > WARN_ON(dev_priv->cdclk.hw.ref != 19200 &&
> > dev_priv->cdclk.hw.ref != 38400);
> > break;
> > + case 180000:
> > case 312000:
> > case 552000:
> > case 648000:
> > WARN_ON(dev_priv->cdclk.hw.ref != 24000);
> > + break;
> > + case 192000:
> > + WARN_ON(dev_priv->cdclk.hw.ref != 19200 &&
> > + dev_priv->cdclk.hw.ref != 38400 &&
> > + dev_priv->cdclk.hw.ref != 24000);
> > }
> >
> > ratio = cdclk / (dev_priv->cdclk.hw.ref / 2);
> > --
> > 2.22.0
> >
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