Re: [PATCH v2] drm/i915: State readout and cross-checking for dp_m2_n2

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

On Mon, May 05, 2014 at 01:49:31PM +0530, Vandana Kannan wrote:
> Adding relevant read out comparison code, in check_crtc_state, for the new
> member of crtc_config, dp_m2_n2, which was introduced to store link_m_n
> values for a DP downclock mode (if available). Suggested by Daniel.
> 
> v2: Changed patch title.
> Daniel's review comments incorporated.
> Added relevant state readout code for M2_N2. dp_m2_n2 comparison to be done
> only when high RR is not in use (This is because alternate m_n register
> programming will be done only when low RR is being used).
> 
> Signed-off-by: Vandana Kannan <vandana.kannan@intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/i915/intel_ddi.c     |  1 +
>  drivers/gpu/drm/i915/intel_display.c | 72 +++++++++++++++++++++++++++++++++---
>  drivers/gpu/drm/i915/intel_dp.c      |  2 +
>  drivers/gpu/drm/i915/intel_drv.h     |  2 +
>  4 files changed, 72 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 0ad4e96..6784f0b 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1587,6 +1587,7 @@ void intel_ddi_get_config(struct intel_encoder *encoder,
>  	case TRANS_DDI_MODE_SELECT_DP_MST:
>  		pipe_config->has_dp_encoder = true;
>  		intel_dp_get_m_n(intel_crtc, pipe_config);
> +		intel_dp_get_m2_n2(intel_crtc, pipe_config);
>  		break;
>  	default:
>  		break;
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 797f01c..2e625eb 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -6670,6 +6670,34 @@ void intel_dp_get_m_n(struct intel_crtc *crtc,
>  					     &pipe_config->dp_m_n);
>  }
>  
> +void intel_dp_get_m2_n2(struct intel_crtc *crtc,
> +		      struct intel_crtc_config *pipe_config)
> +{
> +	struct drm_device *dev = crtc->base.dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	enum transcoder transcoder = pipe_config->cpu_transcoder;
> +
> +	if (INTEL_INFO(dev)->gen >= 8) {
> +		intel_cpu_transcoder_get_m_n(crtc, transcoder,
> +						&pipe_config->dp_m_n);

dm_m2_n2 surely? And why do we even want to do this?

> +	} else if (INTEL_INFO(dev)->gen > 6) {
> +		pipe_config->dp_m2_n2.link_m =
> +					I915_READ(PIPE_LINK_M2(transcoder));
> +		pipe_config->dp_m2_n2.link_n =
> +					I915_READ(PIPE_LINK_N2(transcoder));
> +		pipe_config->dp_m2_n2.gmch_m =
> +					I915_READ(PIPE_DATA_M2(transcoder))
> +					& ~TU_SIZE_MASK;
> +		pipe_config->dp_m2_n2.gmch_n =
> +					I915_READ(PIPE_DATA_N2(transcoder));
> +		pipe_config->dp_m2_n2.tu =
> +					((I915_READ(PIPE_DATA_M2(transcoder))
> +					& TU_SIZE_MASK) >> TU_SIZE_SHIFT) + 1;
> +	}
> +
> +}
>
> +
>  static void ironlake_get_fdi_m_n_config(struct intel_crtc *crtc,
>  					struct intel_crtc_config *pipe_config)
>  {
> @@ -9169,6 +9197,15 @@ static void intel_dump_pipe_config(struct intel_crtc *crtc,
>  		      pipe_config->dp_m_n.gmch_m, pipe_config->dp_m_n.gmch_n,
>  		      pipe_config->dp_m_n.link_m, pipe_config->dp_m_n.link_n,
>  		      pipe_config->dp_m_n.tu);
> +
> +	DRM_DEBUG_KMS("dp: %i, gmch_m2: %u, gmch_n2: %u, link_m2: %u, link_n2: %u, tu2: %u\n",
> +		      pipe_config->has_dp_encoder,
> +		      pipe_config->dp_m2_n2.gmch_m,
> +		      pipe_config->dp_m2_n2.gmch_n,
> +		      pipe_config->dp_m2_n2.link_m,
> +		      pipe_config->dp_m2_n2.link_n,
> +		      pipe_config->dp_m2_n2.tu);
> +
>  	DRM_DEBUG_KMS("requested mode:\n");
>  	drm_mode_debug_printmodeline(&pipe_config->requested_mode);
>  	DRM_DEBUG_KMS("adjusted mode:\n");
> @@ -9533,6 +9570,14 @@ intel_pipe_config_compare(struct drm_device *dev,
>  			  struct intel_crtc_config *current_config,
>  			  struct intel_crtc_config *pipe_config)
>  {
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct intel_connector *intel_connector = dev_priv->drrs.connector;
> +	struct intel_encoder *encoder = (intel_connector != NULL) ?
> +			intel_attached_encoder(&intel_connector->base) :
> +			NULL;
> +	struct intel_dp *intel_dp = (encoder != NULL) ?
> +			enc_to_intel_dp(&encoder->base) : NULL;
> +
>  #define PIPE_CONF_CHECK_X(name)	\
>  	if (current_config->name != pipe_config->name) { \
>  		DRM_ERROR("mismatch in " #name " " \
> @@ -9583,11 +9628,28 @@ intel_pipe_config_compare(struct drm_device *dev,
>  	PIPE_CONF_CHECK_I(fdi_m_n.tu);
>  
>  	PIPE_CONF_CHECK_I(has_dp_encoder);
> -	PIPE_CONF_CHECK_I(dp_m_n.gmch_m);
> -	PIPE_CONF_CHECK_I(dp_m_n.gmch_n);
> -	PIPE_CONF_CHECK_I(dp_m_n.link_m);
> -	PIPE_CONF_CHECK_I(dp_m_n.link_n);
> -	PIPE_CONF_CHECK_I(dp_m_n.tu);
> +
> +
> +	/* DP M1_N1 registers are used when DRRS is disabled or when high RR
> +	 * is used. Else, DP M2_N2 registers are used. The following check
> +	 * has been added to make sure a mismatch (if any) is displayed only
> +	 * for a real difference and not because of DRRS state.
> +	 */
> +	if ((dev_priv->vbt.drrs_type == DRRS_NOT_SUPPORTED) ||
> +		(dev_priv->vbt.drrs_type != DRRS_NOT_SUPPORTED && intel_dp &&
> +		intel_dp->drrs_state.refresh_rate_type == DRRS_HIGH_RR)) {
> +			PIPE_CONF_CHECK_I(dp_m_n.gmch_m);
> +			PIPE_CONF_CHECK_I(dp_m_n.gmch_n);
> +			PIPE_CONF_CHECK_I(dp_m_n.link_m);
> +			PIPE_CONF_CHECK_I(dp_m_n.link_n);
> +			PIPE_CONF_CHECK_I(dp_m_n.tu);
> +	} else {
> +		PIPE_CONF_CHECK_I(dp_m2_n2.gmch_m);
> +		PIPE_CONF_CHECK_I(dp_m2_n2.gmch_n);
> +		PIPE_CONF_CHECK_I(dp_m2_n2.link_m);
> +		PIPE_CONF_CHECK_I(dp_m2_n2.link_n);
> +		PIPE_CONF_CHECK_I(dp_m2_n2.tu);
> +	}

Can't we just check both dp_m_n and dp_m2_n2 always?

>  
>  	PIPE_CONF_CHECK_I(adjusted_mode.crtc_hdisplay);
>  	PIPE_CONF_CHECK_I(adjusted_mode.crtc_htotal);
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 34ed143..9aa4dcd 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1511,6 +1511,8 @@ static void intel_dp_get_config(struct intel_encoder *encoder,
>  
>  	intel_dp_get_m_n(crtc, pipe_config);
>  
> +	intel_dp_get_m2_n2(crtc, pipe_config);
> +
>  	if (port == PORT_A) {
>  		if ((I915_READ(DP_A) & DP_PLL_FREQ_MASK) == DP_PLL_FREQ_160MHZ)
>  			pipe_config->port_clock = 162000;
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index d8b540b..1013f70 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -763,6 +763,8 @@ void hsw_enable_pc8(struct drm_i915_private *dev_priv);
>  void hsw_disable_pc8(struct drm_i915_private *dev_priv);
>  void intel_dp_get_m_n(struct intel_crtc *crtc,
>  		      struct intel_crtc_config *pipe_config);
> +void intel_dp_get_m2_n2(struct intel_crtc *crtc,
> +		      struct intel_crtc_config *pipe_config);
>  int intel_dotclock_calculate(int link_freq, const struct intel_link_m_n *m_n);
>  void
>  ironlake_check_encoder_dotclock(const struct intel_crtc_config *pipe_config,
> -- 
> 1.9.2
> 
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-- 
Ville Syrjälä
Intel OTC