Re: [PATCH 2/2] drm/i915/psr: program vsc header for psr2

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 21 Dec 2016, vathsala nagaraju <vathsala.nagaraju@intel.com> wrote:
> Function hsw_psr_setup handles vsc header setup for psr1 and
> skl_psr_setup_vsc handles vsc header setup for psr2.
>
> Setup VSC header in function skl_psr_setup_vsc for psr2 support,
> as per edp 1.4 spec, table 6-11:VSC SDP HEADER Extension for psr2
> operation.
>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Jim Bride <jim.bride@linux.intel.com>
> Signed-off-by: Vathsala Nagaraju <vathsala.nagaraju@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h  |  2 ++
>  drivers/gpu/drm/i915/intel_dp.c  | 24 ++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_psr.c | 17 +++++++++++++++--
>  3 files changed, 41 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 77d7a07..95ff959 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1232,6 +1232,8 @@ struct i915_psr {
>  	bool psr2_support;
>  	bool aux_frame_sync;
>  	bool link_standby;
> +	bool y_cord_support;
> +	bool colorimetry_support;
>  };
>  
>  enum intel_pch {
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 66b5bc8..0c9bb66 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -3041,6 +3041,22 @@ static void chv_dp_post_pll_disable(struct intel_encoder *encoder,
>  				DP_LINK_STATUS_SIZE) == DP_LINK_STATUS_SIZE;
>  }
>  
> +bool intel_dp_get_y_cord_status(struct intel_dp *intel_dp)

static. Sparse would have told you about this.

> +{
> +	uint8_t psr_caps;

Please initialize psr_caps = 0 to default to false in case aux fails. If
the compiler is smart enough, it might even warn you about this.

> +
> +	drm_dp_dpcd_readb(&intel_dp->aux, DP_PSR_CAPS, &psr_caps);
> +	return (psr_caps & DP_PSR_Y_COORDINATE);

Unnecessary braces.

> +}
> +
> +bool intel_dp_get_colorimetry_status(struct intel_dp *intel_dp)
> +{
> +	uint8_t dprx;
> +
> +	drm_dp_dpcd_readb(&intel_dp->aux, DPRX_FEATURE_ENUMERATION_LIST, &dprx);
> +	return (dprx & VSC_SDP_EXT_FOR_COLORIMETRY_SUPPORTED);

Same things here as in intel_dp_get_y_cord_status.

> +}
> +
>  /* These are source-specific values. */
>  uint8_t
>  intel_dp_voltage_max(struct intel_dp *intel_dp)
> @@ -3619,6 +3635,14 @@ void intel_dp_set_idle_link_train(struct intel_dp *intel_dp)
>  		dev_priv->psr.psr2_support = dev_priv->psr.aux_frame_sync;
>  		DRM_DEBUG_KMS("PSR2 %s on sink",
>  			      dev_priv->psr.psr2_support ? "supported" : "not supported");
> +
> +		if (dev_priv->psr.psr2_support) {
> +			dev_priv->psr.y_cord_support =
> +			intel_dp_get_y_cord_status(intel_dp);
> +			dev_priv->psr.colorimetry_support =
> +			intel_dp_get_colorimetry_status(intel_dp);

The indentation doesn't seem to be right for the continuation lines.

> +		}
> +
>  	}
>  
>  	/* Read the eDP Display control capabilities registers */
> diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
> index 6aca8ff..c3aa649 100644
> --- a/drivers/gpu/drm/i915/intel_psr.c
> +++ b/drivers/gpu/drm/i915/intel_psr.c
> @@ -122,13 +122,26 @@ static void vlv_psr_setup_vsc(struct intel_dp *intel_dp)
>  static void skl_psr_setup_su_vsc(struct intel_dp *intel_dp)
>  {
>  	struct edp_vsc_psr psr_vsc;
> +	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
> +	struct drm_device *dev = intel_dig_port->base.base.dev;
> +	struct drm_i915_private *dev_priv = to_i915(dev);
>  
>  	/* Prepare VSC Header for SU as per EDP 1.4 spec, Table 6.11 */
>  	memset(&psr_vsc, 0, sizeof(psr_vsc));
>  	psr_vsc.sdp_header.HB0 = 0;
>  	psr_vsc.sdp_header.HB1 = 0x7;
> -	psr_vsc.sdp_header.HB2 = 0x3;
> -	psr_vsc.sdp_header.HB3 = 0xb;
> +	if (dev_priv->psr.colorimetry_support &&
> +		dev_priv->psr.y_cord_support) {
> +		psr_vsc.sdp_header.HB2 = 0x5;
> +		psr_vsc.sdp_header.HB3 = 0x13;
> +	} else if (dev_priv->psr.y_cord_support) {
> +		psr_vsc.sdp_header.HB2 = 0x4;
> +		psr_vsc.sdp_header.HB3 = 0xe;
> +	} else {
> +		psr_vsc.sdp_header.HB2 = 0x3;
> +		psr_vsc.sdp_header.HB3 = 0xc;
> +	}

Rodrigo, I'm leaving the review of these to you. ;)

BR,
Jani.


> +
>  	intel_psr_write_vsc(intel_dp, &psr_vsc);
>  }

-- 
Jani Nikula, Intel Open Source Technology Center
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