Re: [PATCH 6/7] drm/i915/display/tgl: Fix the order of the step to turn transcoder clock off

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

On Fri, Nov 22, 2019 at 04:54:58PM -0800, José Roberto de Souza wrote:
> For TGL the step to turn off the transcoder clock was moved to after
> the complete shutdown of DDI. Only the MST slave transcoders should
> disable the clock before that.
> 
> BSpec: 49190
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c    |  9 ++++++++-
>  drivers/gpu/drm/i915/display/intel_dp_mst.c | 15 ++++++++++++---
>  2 files changed, 20 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index cfcaa7c81575..aa0249333175 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3813,7 +3813,7 @@ static void intel_ddi_post_disable_dp(struct intel_encoder *encoder,
>  	 */
>  	intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
>  
> -	if (!is_mst)
> +	if (INTEL_GEN(dev_priv) < 12 && !is_mst)
>  		intel_ddi_disable_pipe_clock(old_crtc_state);
>  
>  	intel_disable_ddi_buf(encoder, old_crtc_state);
> @@ -3826,6 +3826,13 @@ static void intel_ddi_post_disable_dp(struct intel_encoder *encoder,
>  		intel_display_power_put_unchecked(dev_priv,
>  						  dig_port->ddi_io_power_domain);
>  
> +	/*
> +	 * From TGL BSpec "If single stream or multi-stream master transcoder:
> +	 * Configure Transcoder Clock select to direct no clock to the
> +	 * transcoder"
> +	 */

Not really convinced these comments add anything the code isn't already saying.

> +	if (INTEL_GEN(dev_priv) >= 12)
> +		intel_ddi_disable_pipe_clock(old_crtc_state);

That's much later than the bspec sequence suggests.

>  	intel_ddi_clk_disable(encoder);
>  	tgl_clear_psr2_transcoder_exitline(old_crtc_state);
>  }
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 94549848653a..53afe3e179f7 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -369,8 +369,19 @@ static void intel_mst_post_disable_dp(struct intel_encoder *encoder,
>  	struct intel_dp *intel_dp = &intel_dig_port->dp;
>  	struct intel_connector *connector =
>  		to_intel_connector(old_conn_state->connector);
> +	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>  
> -	intel_ddi_disable_pipe_clock(old_crtc_state);
> +	intel_dp->active_mst_links--;
> +
> +	/*
> +	 * From TGL BSpec "If multi-stream slave transcoder: Configure
> +	 * Transcoder Clock Select to direct no clock to the transcoder"
> +	 *
> +	 * From older GENs BSpec "Configure Transcoder Clock Select to direct
> +	 * no clock to the transcoder"
> +	 */
> +	if (INTEL_GEN(dev_priv) < 12 || intel_dp->active_mst_links)

Maybe we should add 'last_mst_stream' to mirror the 'first_mst_stream'
in the enable code?

> +		intel_ddi_disable_pipe_clock(old_crtc_state);
>  
>  	/* this can fail */
>  	drm_dp_check_act_status(&intel_dp->mst_mgr);
> @@ -386,8 +397,6 @@ static void intel_mst_post_disable_dp(struct intel_encoder *encoder,
>  	drm_dp_send_power_updown_phy(&intel_dp->mst_mgr, connector->port,
>  				     false);
>  
> -	intel_dp->active_mst_links--;
> -
>  	intel_mst->connector = NULL;
>  	if (intel_dp->active_mst_links == 0) {
>  		intel_dig_port->base.post_disable(&intel_dig_port->base,
> -- 
> 2.24.0
> 
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-- 
Ville Syrjälä
Intel
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