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

Souza, Jose
2019-06-24T21:05:27Z

On Mon, 2019-06-24 at 15:39 +0300, Ville Syrjälä wrote:
> On Thu, Jun 20, 2019 at 11:33:27PM +0000, Souza, Jose wrote:
> > 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?
>
> Try to load/resume the audio driver when cdclk is low maybe?

Oh good idea.

It worked, snd_hda_intel loaded without errors while cdclk was 172800
kHz and then connecting a monitor with audio the cdclk was set to
192000 kHz and audio was send to speakers.

>
> > > > 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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