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

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

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@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>

Ok, this patch seems right according to spec.

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@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?

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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