Re: [Intel-gfx] [PATCH 1/3] drm/i915/display/adl_s: Fix dpclka_cfgcr0_clk_off mapping

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Feb 12, 2021 at 07:42:17PM +0000, Souza, Jose wrote:
> On Fri, 2021-02-12 at 21:20 +0200, Ville Syrjälä wrote:
> > On Fri, Feb 12, 2021 at 10:21:59AM -0800, José Roberto de Souza wrote:
> > > The cfgcr0/1_clk_off mapping is wrong for adl-s what could cause
> > > the wrong clock being disabled and leaving a not needed clock
> > > running consuming more power than needed.
> > > 
> > > Bspec: 50287
> > > Bspec: 53812
> > > Bspec: 53723
> > > Fixes: d6d2bc996e45 ("drm/i915/adl_s: Configure Port clock registers for ADL-S")
> > > Cc: Aditya Swarup <aditya.swarup@intel.com>
> > > Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> > > Cc: Matt Roper <matthew.d.roper@intel.com>
> > > Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/display/intel_ddi.c |  4 +++-
> > >  drivers/gpu/drm/i915/i915_reg.h          | 12 ++++++++++++
> > >  2 files changed, 15 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> > > index 2d6906f6995f..7631e080349d 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > > @@ -1585,7 +1585,9 @@ hsw_set_signal_levels(struct intel_dp *intel_dp,
> > >  static u32 icl_dpclka_cfgcr0_clk_off(struct drm_i915_private *dev_priv,
> > >  				     enum phy phy)
> > >  {
> > > -	if (IS_ROCKETLAKE(dev_priv)) {
> > > +	if (IS_ALDERLAKE_S(dev_priv)) {
> > > +		return ADLS_DPCLKA_CFGCR_DDI_CLK_OFF(phy);
> > > +	} else if (IS_ROCKETLAKE(dev_priv)) {
> > >  		return RKL_DPCLKA_CFGCR0_DDI_CLK_OFF(phy);
> > >  	} else if (intel_phy_is_combo(dev_priv, phy)) {
> > >  		return ICL_DPCLKA_CFGCR0_DDI_CLK_OFF(phy);
> > > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > > index 224ad897af34..7c69b50ccc5c 100644
> > > --- a/drivers/gpu/drm/i915/i915_reg.h
> > > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > > @@ -10416,6 +10416,18 @@ enum skl_power_gate {
> > >  							ADLS_DPCLKA_DDIJ_SEL_MASK, \
> > >  							ADLS_DPCLKA_DDIK_SEL_MASK)
> > >  
> > > 
> > > +#define _ADLS_DPCLKA_DDIA_CLK_OFF			REG_BIT(10)
> > > +#define _ADLS_DPCLKA_DDIB_CLK_OFF			REG_BIT(11)
> > > +#define _ADLS_DPCLKA_DDII_CLK_OFF			REG_BIT(24)
> > > +#define _ADLS_DPCLKA_DDIJ_CLK_OFF			REG_BIT(4)
> > > +#define _ADLS_DPCLKA_DDIK_CLK_OFF			REG_BIT(5)
> > 
> > So shose are apparently split between the two registers. Why aren't
> > we defining these so that it would be obvious which register they
> > live in? This stuff is confusing enough with the hw folks churning
> > the bits around randomly on every platform, so I don't think we
> > should add to the confusion by obfuscating the bit defines. I do
> > like that you named the bits, which isn't case for the other
> > platforms. Would be nice to fix it all up actually.
> > 
> > Hmm. However, this new defintion seem to match 
> > ICL_DPCLKA_CFGCR0_DDI_CLK_OFF() 100%. So how can this be fixing
> > something? Also ICL for sure can't have that many combo PHYs can
> > it? We should nuke the extra stuff from the ICL defintion if it's
> > no longer used.
> 
> Good catch & my bad.
> Was fixing it for other platform and tought that it might be broken
> for ADL-S too but as all ports are combo ports
> ICL_DPCLKA_CFGCR0_DDI_CLK_OFF will do the right job.
> 
> Dropping this patch.

I wouldn't mind having this patch, or rather a patch to clean up/clarify
all the DPCLKA_CFGCR bits on every platform. As it stands cross checking
against the spec is a bit tedious.

But at least right now I don't have to rebase my DDI clock routing
series [1] :) That one still has a few trivial patches looking for review
btw *wink* *nudge*.

[1] https://patchwork.freedesktop.org/series/86544/

-- 
Ville Syrjälä
Intel
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