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

[Runyan, Arthur J]

I'll check on it.

> -----Original Message-----
> From: Souza, Jose
> Sent: Thursday, 29 November, 2018 3:47 PM
> To: Vivi, Rodrigo <rodrigo.vivi at intel.com>
> Cc: dri-devel at lists.freedesktop.org; intel-gfx at lists.freedesktop.org;
> Runyan, Arthur J <arthur.j.runyan at intel.com>; Pandiyan, Dhinakaran
> <dhinakaran.pandiyan at intel.com>
> Subject: Re: [PATCH 4/9] drm/i915/icl: Do not change reserved registers
> related to PSR2
> 
> 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
> > >