[Intel-gfx] [PATCH 4/9] drm/i915/icl: Do not change reserved registers related to PSR2

[Souza, Jose]

On Thu, 2018-11-29 at 14:15 -0800, Rodrigo Vivi wrote:
> On Mon, Nov 26, 2018 at 04:37:05PM -0800, José Roberto de Souza
> wrote:
> > For ICL the bit 12 of CHICKEN_TRANS is reserved so we should not
> > touch it and as by default VSC_DATA_SEL_SOFTWARE_CONTROL is already
> > unset in gen10 + GLK we can just drop it and fix for both gens.
> > 
> > Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> 
> Ok, this patch seems right according to spec.
> 
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> 
> But I wonder now if we need intel_psr_setup_vsc() at all for
> platforms different than gen9.
> 
> Because description of this bit is:
> This field enables the programmable header for the PSR2 VSC packet.
> 
> Without the programmable version I would assume display
> engine is now responsible for setting header entirely?

As this was in a chicken register in gen 9 my guess is that it was
fixed on newer gens and as it is required for PSR2 we don't need to
manually enable it in driver but Art could confirm it.

> 
> Art?
> 
> > ---
> >  drivers/gpu/drm/i915/intel_psr.c | 11 ++++-------
> >  1 file changed, 4 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_psr.c
> > b/drivers/gpu/drm/i915/intel_psr.c
> > index 607c3ec41679..7607a58a6ec0 100644
> > --- a/drivers/gpu/drm/i915/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/intel_psr.c
> > @@ -635,17 +635,14 @@ static void intel_psr_enable_source(struct
> > intel_dp *intel_dp,
> >  	if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv))
> >  		hsw_psr_setup_aux(intel_dp);
> >  
> > -	if (dev_priv->psr.psr2_enabled) {
> > +	if (dev_priv->psr.psr2_enabled && (IS_GEN9(dev_priv) &&
> > +					   !IS_GEMINILAKE(dev_priv))) {
> >  		i915_reg_t reg = gen9_chicken_trans_reg(dev_priv,
> >  							cpu_transcoder)
> > ;
> >  		u32 chicken = I915_READ(reg);
> >  
> > -		if (IS_GEN9(dev_priv) && !IS_GEMINILAKE(dev_priv))
> > -			chicken |= (PSR2_VSC_ENABLE_PROG_HEADER
> > -				   | PSR2_ADD_VERTICAL_LINE_COUNT);
> > -
> > -		else
> > -			chicken &= ~VSC_DATA_SEL_SOFTWARE_CONTROL;
> > +		chicken |= PSR2_VSC_ENABLE_PROG_HEADER |
> > +			   PSR2_ADD_VERTICAL_LINE_COUNT;
> >  		I915_WRITE(reg, chicken);
> >  	}
> >  
> > -- 
> > 2.19.2
> > 
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